But the established late-night lineup - "Tonight," "The Arsenio Hall Show" and "Nightline" - remains as competitive as ever. So who's next?
There's movie comedian Whoopi Goldberg, scheduled to begin her own show in September. There's Rush Limbaugh, the Morton Downey Jr. of the '90s, who's also slated to begin a show in the fall.
Maybe they can make it in the fickle late-night time period, though in recent years it has rejected all "Tonight Show" competitors save for ABC News' "Nightline," which debuted in 1980, and "The Arsenio Hall Show," which evolved out of the ill-fated "Joan Rivers Show" in 1989.
The new competitors each bring something different to the late-night mix, which will improve their chances for survival.
Goldberg, whose syndicated show debuts at 11 p.m. Sept. 14 on Channel 29, has no skills as a host but a ready-made audience of movie fans. She'll be the only female late-night host, but it's anybody's guess if that's a plus to the audience, which is dominated by young men.
And Limbaugh, whose nationally syndicated radio program is popular with irate reactionaries everywhere, plans a newsier, phone-in talkfest, instead of the usual entertainment mix. His show debuts 1:30 a.m. Sept. 15, also on Channel 29.
Projected for 1993: Chevy Chase's late-night talk show, produced by the Fox network. Chase, who was at his best performing in the sketch comedy of the early "Saturday Night Live," may flourish again in this format.
Miller, also an "SNL" alumnus, didn't fare too well. His syndicator, Tribune Entertainment, had hoped his initially poor ratings would get a boost
from folks who switched from Jay Leno's "Tonight." But Miller's numbers kept falling.
Old habits die hard. Despite generally negative reviews for Leno's work on ''Tonight," the NBC show's ratings have remained steady since Carson's departure.
For Leno's first eight weeks as the new "Tonight Show" host, the local ratings were 6 Nielsen points (about 150,000 households in the Philadelphia area) and a 16 percent share of the viewing audience. The numbers were exactly the same one year ago when Carson was host.
For the same period, competitor "Arsenio" has declined slightly, from 4/ 11 to 3/9; the "Nightline" audience has grown, undoubtedly because of its feverish election-year coverage, from 6/16 to 8/19.
"Dennis Miller" went nowhere. It rated 1/3, compared to the 2/7 won last year by 20-year-old reruns of "All in the Family" on Channel 57. Miller's last new show will air at 11:30 p.m. tomorrow; he'll air in reruns for the rest of the summer.
Though Leno hasn't done any worse than Carson, whose ratings were in decline until he announced his retirement last year, it's unlikely he or anyone else will ever match the consistently high ratings Carson won in his 1970s heyday, when the networks had much less competition for late-night viewers from cable or syndicated programs.
Leno, always sharp and funny in his years as Carson's guest host, has crumbled a bit under the pressure of hosting "Tonight" every night.
It didn't help that the months preceding Leno's debut were filled with weepy appreciations of Carson. And Leno does suffer from the inevitable comparisons to Carson's skills, polished over 30 years on nightly television.
But Leno also suffers from comparisons to Leno - the old Leno. His monologues were once slightly offbeat and razor-sharp. Now he plays it safe with the expected Dan Quayle jokes, and sometimes appears frantic in his attempts to please every single guest and audience member.
He has improved the show in one important way, insisting on more unusual and informative guests. Carson always had old ladies from the Midwest on with the usual movie stars, but Leno picks a more influential group of academics,
artists and journalists to share the chairs with Tom Cruise or Goldie Hawn. ''This is the kind of stuff I'm really interested in," he gushed to Penn professor Kathleen Hall Jamieson, on recently to discuss political advertising.
His musical tastes are likewise more intriguing: rappers, jazz musicians and college-radio rock bands have edged out the Lola Falana types that used to appear.
One gets the feeling that when the audience and NBC executives stop scrutinizing Leno's "Tonight Show," he'll relax a bit, and the show will settle into a comfortable groove.
That prospect must unnerve the host of "The Arsenio Hall Show." He's tried in vain to spark a feud between himself and Leno.
Commenting on Miller's cancellation, Hall told his audience Friday: "He should be staying, and that punk-ass Leno should be going."
If Hall could back up that bluster with a strong show, he might be more convincing. But Hall's monologues are self-aggrandizing. For a comedian, his approach to news is surprisingly sanctimonious. In his schmoozy interviews, he never asks follow-up questions, which leads to a lot of long, awkward silences.
His only successful interviews are those in which the guest takes total control and Hall doesn't have to ask any questions.
Unlike Leno's "Tonight," "Arsenio" seems unlikely to evolve into anything better. As his ratings begin to dip, Hall may realize this himself - he's reportedly thinking about bowing out next year.
Whatever he does, the after-the-news scene is likely to get more competitive. In addition to this fall's newcomers, there is the intriguing prospect of David Letterman quitting his job at NBC's "Late Night" when his contract expires next spring.
Letterman would then be free to sell his skills to ABC - which since the Rick Dees fiasco has needed something strong and fun to follow "Nightline" - or to CBS, which since its Pat Sajak fiasco has messed around with a variety of programs and has settled, for now, on low-rent "crime time after prime time" dramas.
Whoever is brave enough to hire the infamously irascible Letterman would finally have a real challenger to "The Tonight Show."