Martha Stewart is endlessly successful, and unavoidable to boot.

Martha Stewart has destroyed her career.

Martha is coming back huger than ever.

Martha's not that big anymore.

And there you have one of the problems with conventional wisdom -- it's forever in flux; each of the above assessments has been widespread at some point over the past few years. In fact, few public figures have fluctuated more wildly on that scale than Stewart, who's widely regarded as either America's Comfort Queen or its Kitchen Witch, or maybe a little bit of each.

There's room for debate about the size of Stewart's current public following and her future as a prime-time TV commodity. But a little more than a month ago, she was on a roll by almost any standard: Her ankle bracelet came off on Sept. 1 -- she was completing a nearly six-month term of home confinement after serving five months in prison for lying to authorities about a stock deal. And she, along with her producer, the highly successful Mark Burnett ("Survivor"), and seemingly all of NBC, was looking forward to the Sept. 21 debut of her big prime-time reality show, "The Apprentice: Martha Stewart."

A colder reality emerged with the Sept. 22 overnight ratings. Stewart and her "Apprentice" had landed with a large and unexpected splat.

NBC would put that differently, but in other quarters there is little disagreement. Variety has called the show the biggest bomb of the new season. Heralding as it did Stewart's return to public life -- and her first regular incursion into prime time -- the series was one of the highest-profile of the new season, and yet its debut attracted only 7.1 million viewers. Week 2 saw a falloff to 6.1 million. Reruns of "Lost" airing opposite the show on ABC were drawing about twice the viewership. By the second week, Stewart's "Apprentice" placed fourth in the time slot.

"There was a lot of talk about her comeback," says Lisa Quan, vice president and associate director for broadcast research at Magna Global, a media negotiation company. "I don't think NBC expected the numbers to be this disappointing."

But just what did NBC expect?

Burnett told a reporter in early September that tracking data placed Stewart's show as the top new fall series. That information, he said in a later conversation, had been supplied to him by the network.

"I never saw the tracking," he said. "But the actual business analysis did not mirror the hyperbole" of what NBC projected. "In a business sense," he continued, "7 million prime-time Martha viewers are very valuable to us. Martha's transaction base with viewers is very high. While we'd be even more delighted with twice the numbers, this is very valuable."

What he's saying is that Stewart viewers purchase a lot of the products they see on her show -- more, on average, than do viewers of other programs.

From Quan's more neutral perspective, Stewart's series "hasn't performed to our expectations, but this season even the Donald Trump version of 'The Apprentice' hasn't performed as well as we thought it would. We knew there'd be some dropoff in his show, but we didn't expect this much."

Trump's show averaged more than 20 million viewers a week during its first edition, and last spring was still pulling in close to 14 million; this fall it has been averaging around 10 million.

"The expectation," Quan says of Stewart's series, "was that it would do fairly well -- that it wouldn't do gangbusters, but fairly well. Bringing in a second version of anything . . . in the movies in most cases you can't expect the sequel to do as well as the first one."

NBC injected yet another wrinkle into the equation last week, when it moved the Stewart "Apprentice" from 8 to 9 p.m. Wednesdays, swapping places with "The E-Ring," which had been underperforming at the later hour. At that point some observers concluded that the network had given up on the show. After all, it was getting trounced at 8 by reruns of "Lost." In the new time slot, its No. 1 competitor would be original episodes of that show.

In fact, says NBC Entertainment President Kevin Reilly, the move was a very basic programming decision: There was reality competition for Stewart at 8 in the form of Fox's "So You Think You Can Dance," which has since concluded, and UPN's "America's Next Top Model." And there was considerably more dramatic competition for "E-Ring" at 9.

Amid forecasts of doom, Burnett has remained guardedly hopeful.

"It's not over yet, and it's . . . possible this move might help," he said early last week, "although quite frankly I wish they'd left us at 8 o'clock. . . . Even though we'll be up against 'Lost,' maybe at 9 o'clock we'll find a different viewer."

At least that first time out, the move didn't cut into Stewart's ratings. She pulled in 6.3 million viewers, actually a small improvement over the previous week. Three weeks' worth of numbers begin to suggest that she has her audience of 6 million to 7 million viewers, and they'll follow her wherever she goes.

The schedule shift "absolutely was a benefit," says Tom Bierbaum, NBC's vice president for ratings and program information. "We focus on the rating in the adult 18-to-49 demographic, and she was up 19 percent there."

In fact Stewart had her best week yet with the 18-to-49 crowd, pulling an overall 2.5 rating. More encouraging still, he said, was that she gained in that demographic from one half-hour to the other, recording a 2.9 in the second half of her broadcast.

That's fine as far as it goes, but NBC averaged a 3.6 rating among 18-to-49-year-olds last season in the time slot, and a 3.6 is less than spectacular. Although nobody at the network will say so, it seems clear that a season's worth of 2.5s, or even 2.9s, isn't going to make anybody happy.

Sometime around midseason -- the show's publicist says the timing hasn't been decided -- Stewart will select her winning apprentice and put him or her to work doing whatever an apprentice to Martha does, bringing the first edition of her prime-time experience to an end.

"We've only contemplated one edition of the show," says Reilly.

Which brings back the question of what NBC was expecting when it scheduled the show. Stewart's name is among the more instantly recognizable in American culture, to be sure. Her eponymous magazine, Martha Stewart Living, sells around 2 million copies a month, which is a lot of magazines. Her books (the latest, "The Martha Rules: 10 Essentials for Achieving Success as You Start, Grow, or Manage a Business," has just been released) find a solid readership. But a format that fosters dog-eat-dog competition, major backbiting and a weekly opportunity for the star to kill off the loser may not be the ideal venue for a woman who's made her career dispensing comforts to her admirers.

Was there ever a point when she could bring an audience of, say, 15 million to any one venture?

"I don't think so," says Quan, "because Martha's appeal was never with men. And that was the appeal of Donald's version of 'The Apprentice,' that it drew men and women. Martha's appeal is with women -- and not younger women."

For now, though, Stewart isn't going anywhere. She's promoting the new book, her magazines -- there are several others, among them Martha Stewart Weddings and Everyday Food -- retain their place on the newsstand, and her new syndicated daytime show, "Martha," continues to draw solid though unspectacular early ratings. And tonight the fourth installment of "The Apprentice: Martha Stewart" will air at 9 o'clock. Which, to hear NBC tell it, is at least a pretty good thing.

"We're definitely not disappointed in the quality of the show," says Reilly. "We've seen most of the episodes at this point, and we feel we're delivering the goods, or Mark Burnett's delivering the goods. . . . I already am encouraged by the tick-up we saw in the ratings last week. And although this 'Apprentice' is not going to be a phenomenon, I think in the end it will be a success."

Martha Stewart with "Apprentice" archetype Donald Trump.

Martha Stewart with her "Apprentice" contestants at the outset of the show. Though lower than predicted, her ratings have held steady.