There may never have been a television season in which so many good shows bombed. More than 20 different TV series have been introduced and canceled since the beginning of the season in September; the list of casualties includes an unusually high number of programs that tried to be different, unusual or just honorably hilarious.

Some people still go into dank angst over the passing of " Paper Chase" from the CBS schedule last year. That was not compared to the dominoes that have tumbled this year. In a recent Nielsen week, the No. 1 show in the nation was a ya-hoo, outhouse-tilting burlesque comedy called "The Duke of Hazzard." The same week, an outstanding dramatic holdover from last season, "The White Shadow," came in 52nd out of 63 rated shows.

One problem with "The White Shadow" is that it actually tries to be about something. It deals with nuances of human behavior, features characters who are believably flawed and vulnerable, and eschews pat situations and sappily happy endings. That's three kisses of death in a TV series right there. "Shadow" was renewed for next season, but only by the skin of its teeth.

For 30 years, TV critics have wrestled with the public over what should and shouldn't be loved on TV. The public always wins because the networks, justifiably, couldn't care less about pleasing critics. It's too simple and too elitist to say the masses have bad taste, but it may not be an exaggeration to say most viewers wouldn't know a good show when they saw one because they are offered so many bad ones that the few good ones get lost. It could be that viewer expectation have been progressively lowered each year, so that the junk becomes not just increasingly palatable, but so appetizing that anything with a faint gourmet aroma seems off-putting and malodorous. Most TV producers work hardest at trying to get people to accept new minimums; they want to save themselves trouble, money and risk.

They and network executives make it all the harder, then, for a Larry Gelbart and "United States," or a David Gerber and "Eischeid," or an Abby Mann and "Skag," or a James L. Brooks and "The Associates," or a Stelphen J. Cannell and "Tenspeed and Brown Shoe," to name a few of the praiseworthy new shows of 1979-80 either canceled or likely candidates for the graveyard.

Viewers rushed in droves to formula programs like "Flo," "That's Incredible!" and the inexcusably crummy "Trapper John, M.D." from the moment they went on the air. But they were barely willing to sample, much less string along with, such a flawed but promising program as "Pairs", starring one of America's most formidable actors, James Earl Jones.

"Shirley," on NBC, was similar in concept and atmosphere to Abc's "Eight Is Enough," but it was superior in execution -- less cloying, cutesy and corny. Result: "Eight Is Enough" rolls merrily on and "Shirley" has long since been exiled to the Elba of old shows.

"Tenspeed and Brown Shoe" and "Skag" are both peculiar cases. Each premiered as a TV movie on a Sunday night ("Tenspeed" on ABC, "Skag" on NBC) and earned fantastic ratings. But almost as soon as each went into its regular series mode -- whammo -- an iceberg.

In the case of "Skag," viewers may have felt that they learned all they needed to know about steelworker Skag (heroically played by Karl Malden) and family on that first three-hour broadcast. Writer-producer Mann raised more domestic hackles for his hero than there are in all of Eugene O'Neill's plays put together, and although the premiere was powerful and absorbing, the prospect of spending weeks and weeks with this battered clan wasn't particularly attractive. Besides, who wants to set sail on a sea of troubles when the other networks are offering girls in cut-off jeans and chubby-cheeked kiddies and doxens of other reasons not to bother with such exertions as thought or concern? The socially significant problems besieging "Skag" were really no competition for the silly, showboat melodrama of the crises exploding like popcorn on "Dallas."

Those two programs were not in direct competition, but it was the "Dallas" kind of drama -- inflated, dumb and yummy -- that viewers obviously preferred on a weekly basis. We seem in need of shows that provide hissable villains, perhaps as ayatollah surrogates. It may be that an unusually grim news year is partly responsible for the heyday of hokum on television, but then, hokum on television has never been scarce.

It may also be that we are expecting less and less of television and getting it. The peculiar economics of TV always make innovation a risk and imitation desirable; when as many ambitious programs fail as have fallen by the wayside this year, producers feel that much less inclined to try something new the next time.

In a way, the fictional TV series may be becoming an anachronism as a vehicle for anything but zany escapism, through there still remain such isolated exceptions to the rule as "Lou Grant." Otherwise, prime time seems to have been abandoned to the hucksters, shysters and carnies, and the worse it gets, the worse it will get.