At a time when the cable industry's program to wire America is at a critical juncture, the industry seems to have a growing problem with the material that cable brings to the screen.

Although a lot of attention throughout the cable business is focusing on the rising costs of building urban cable systems, and the difficulty of winning and living up to franchise agreements with large municipalities, some industry executives and others see increasing signs of the public's unwillingness to buy cable.

Not only do most cable companies fail miserably at sophisticated approaches to marketing their services, but the public seems to be wondering whether there is really anything there to sell.

For despite all the attention on cable, the dramatic expansion of local systems and a host of new services, cable is reaching about the same percentage of people with access to it as it did two years ago--39 percent of the public. According to a study released here this week, only about 58 percent of the households who can take cable do so, a figure up only 3 percent since 1981.

The study, prepared by the advertising agency Benton & Bowles Inc., suggests even more ominously that the people who have rejected cable are even more negative about it than they were in 1981, when a similar survey was conducted.

Citing the cost of subscription and the fact that they don't need cable for improved reception, 84 percent of the so-called cable rejectors surveyed said they were unlikely to subscribe in the future, a figure up from 79 percent two years ago. And the total of "rejectors" who said they would definitely not subscribe rose from 38 percent two years ago to 43 percent in 1983.

Moreover, potential subscribers increasingly object to the programming content, particularly its suitability for children. Just over a third of those rejecting cable say they would not want their children to see some cable offerings, while 32 percent say they themselves object to cable, presumably its more risque, adult fare.

It is increasingly men, interested in the added sports coverage cable offers, and people wanting access to cable's pay television film products that are pulling in cable subscribers, according to the Benton & Bowles study. About 75 percent of the respondents in the study who signed up for cable in the past two years get at least one pay service.

That, too, is hardly good news for many in the cable business who had viewed the emerging medium as a way to focus programming and advertising on particular audiences, such as women at home during the day. An ABC-Hearst programming effort directed at just such an audience continues to struggle.

But the survey research only tells part of the story. CBS failed at advertiser-supported cable. The lofty, critically praised Entertainment Channel, an RCA-Rockefeller Center service recently failed embarassingly, losing at least $30 million despite Broadway shows, films and British Broadcasting Co. programming.

This recent subscriber to Manhattan Cable, perhaps the nation's most prestigious system because of the New York City audience it serves, has concluded that sports from three sources--ESPN, the Getty Oil station losing millions a month; USA Network, a hodgepodge of entertainment and sports, and Atlanta's WTBS--public affairs and news from Cable News Network and C-SPAN and occasional worthy movies and specials from Home Box Office are the only cable offerings able to pull the dial away from the magnet of network television. MTV's round-the-clock rock serves as background music, an attaction for wide-eyed out of town guests.

Much of the rest of it seems nonsensical. There's the round-the-clock weather and health channels, the local access bill of titillating talk and badly produced community discussion groups, and nonstop want ads for overpriced apartments and summer homes on Long Island. Most of it can barely be classified as either entertaining or informative.

That, then, is cable programming as it stands today. Only the country music of the Group W's Nashville Channel and the family fare of the Disney Channel are missing in Manhattan of the major advertiser supported services, and Showtime and the Disney Channel are the major pay services missing from Time Inc.'s Manhattan Cable lineup.

Put it all together and what's left is, so far, a fairly disappointing picture.

As new cable systems in the big cities become increasingly important over the next year or two, cable's potential to expand television's and, in turn, its viewers' horizons will be sorely tested. The challenge for those hoping to make a buck in cable is to put something appealing on that wire. And soon.