In Greek mythology, hubris is the pride that precedes a fall, usually involving a hero whose arrogance brings down the wrath of the gods.

For the last couple of decades, this has more commonly been known in the media universe as “hosting a talkshow.”

Inevitably, September brings new contenders jockeying to become the next big thing among daytime talkshow hosts. Candidates often come armed with impeccable credentials and ostentatious triumphs in another field.

And most of them fall flat on their faces.

Actors. Comedians. Athletes. Entrepreneurs. Advice experts. News anchors. Politicians. Judges. The talk format, particularly in the daytime, has a way of humbling them all.

This year’s rookie class includes Katie Couric, Jeff Probst, Ricki Lake, Steve Harvey and “conflict resolution” expert Trisha Goddard. Each is being rolled out with the requisite marketing support, and (in most cases) top-flight Q scores.

But then again, the same could be said of Jane Pauley, Tony Danza, Megan Mullally, Wayne Brady, Martin Short and even Rosie O’Donnell, who discovered — in her fleeting cable comeback via OWN — that it’s not always so easy going home again.

Like most things in daytime TV, all roads lead back to Oprah Winfrey. Not only did she set an impossibly high bar for success, but her seal of approval helped launch two of those rare personalities to make it as daytime hosts, Drs. Phil McGraw and Mehmet Oz.

After that, sifting through the wreckage of also-rans, as well as infrequent hits, offers only scant clues regarding what will work or won’t. And given how the marketplace has changed, it’s fair to say even the winners are unlikely to amass the kind of audiences that made “Judge Judy” a household name, much less Oprah a billionaire.

Although a hit talkshow still has the potential to be enormously lucrative — witness the recent TV Guide list placing Judy Sheindlin (“Judge Judy”) and Kelly Ripa among the medium’s highest-paid performers — the syndication market clearly isn’t what it once was.

Local stations have been weakened, and demographics have shifted. Having more women in the workplace has already hastened the demise of the soap opera, with their expensive production pricetags. Talk is cheap, as they say, but the days when daytime could fuel a powerhouse like King World in its heyday appear increasingly distant in the rear-view mirror.

Yes, there are still people home watching TV during the day, but the advertising aimed at them often assumes they’re as likely to need bail bondsmen, drunk-driving attorneys or diet supplements as the products associated with blue-chip advertisers.

So what qualities augur well for the talk class of 2012? Being personable is obviously a good place to start, but that only goes so far. Being a comic is generally an advantage, but few people can be that funny five days a week.

Being a journalist — or at least having an inquisitive nature — helps, but there are never enough newsworthy interview subjects to fully sustain such an enterprise. A gimmick doesn’t hurt, but being too narrowly focused can be confining.

Being trashy has certainly worked before, but stooping to conquer offers no certainty of survival. Besides, wallowing in the misery of others can be a pretty lousy way to live, especially if you’ve already done well enough as to not desperately need the money, a la Couric or Probst.

Finally, there’s almost no substitute for coming to the task fully committed, recognizing the full weight of fronting such an enterprise. Prior to launching his latenight Fox show, Chevy Chase famously confided to friends he could breeze in a couple of hours before taping and be home for dinner. The show was canceled in five weeks.

Many hosts try to enlist the audience as allies. In his Sept. 4 premiere, Harvey sounded a friendly, we’re-all-in-this- together note. “I’m here to help. We’ll get through this thing together ,” he said, citing plans to dispense “common-sense advice.”

Common sense is an underrated attribute, and doubtless of potential value to those available to watch a lot of daytime TV.

In the context of this discussion, however, the first pearl of wisdom would be: Don’t try hosting a talkshow unless you know what you’re signing up for — and prepare to be humbled.