Chief Television Critic Tim Goodman will be writing these journals throughout the Television Critics Association summer press tour, bringing insight, analysis, counter-spin and some snark to the nearly three-week industry presentation.

In Trevor Noah's daunting and important task of replacing Jon Stewart as host of Comedy Central's signature series, The Daily Show, history will reveal that coming out to Los Angeles and having a well-received comedy set and — better for all involved — a well-received panel in front of the nation's television critics and writers, was a masterful public relations gambit and very little else.

All the really hard work comes soon enough. And it will involve shifting demographics and viewing patterns that nobody honestly can control, but will reflect massive stakes for Comedy Central and, probably to a lesser extent, Noah himself.

So all of this talk about how Noah did at TCA is fine — and he successfully established that he's funny and smart and quite charming as well. Those are excellent traits to have, especially if you're a TV host.

But it doesn't drastically help The Daily Show or Comedy Central. Because the show and the channel are facing a much bigger challenge than replacing a host.

Here's the difficult aspect of change — sometimes it doesn't matter how good the new thing is. Sometimes the simple fact that it's new at all is enough for people to look elsewhere — because they don't want new, they want familiar.

This is just human nature, proven endlessly through time. Your favorite gourmet ice cream spot swapped out your particular favorite flavor for something else. Everybody says the new flavor tastes good. And you try it and agree. Except it's not your thing — no offense to the new flavor. So you go there less. Or you go somewhere else. Or, hell, you now get your fix with gelato — which you buy across town and thus never see that gourmet ice cream shop again.

And here's what is likely to happen pretty quickly at Comedy Central: People who "grew up" on or invested a lot of years in Stewart and Stephen Colbert will move on, regardless of the people who replace them. This is already happening with Colbert. Larry Wilmore and The Nightly Show are a different thing entirely and not all of Colbert's fans hung around. And while it's true that The Colbert Report was a singular manifestation of one man's cult of personality, do not kid yourself about the importance of The Daily Show without Stewart.

For a lot of people, Stewart is The Daily Show, end of story. Whatever Noah may have accomplished here at TCA or with his other public relations feats has no bearing on that. Once Stewart goes, a lot of his fans will go, too.

History bears that out. And with history as a guide in dissecting late night comings and goings, you could argue that just as Johnny Carson's people found Jay Leno or David Letterman — and just as Leno and Letterman fans found Jimmy Kimmel or Jimmy Fallon and so on — so too will new fans come to Noah. It's the perpetual shifting of viewing habits, tied both to identity (the host) and the demographic (age) and the available offerings that are out there.

But the Trevor Noah/Comedy Central/Daily Show situation likely goes beyond shifting allegiances. It has a lot more to do with the model than the man. Meaning, most of the viewers involved in the aforementioned example of shuffling late night hosts are of a certain age — and from the oldest to the youngest of that particular bunch, pretty much everybody was "watching TV" because that's what they have always done (save, in this scenario, the very youngest of that demo who are watching only bits of the show online — more on that disaster shortly). Every other viewer in that example, as noted, falls into traditional demographics that watch TV on a TV.

What is likely to happen for Noah and Comedy Central — in fact, something both are predicting — is that his audience will be significantly younger than Stewart's core audience. Obviously some Daily Show fans will stick around and watch Noah and the gang for a while. But those who watched for Stewart — and I would argue that's the bulk of the current audience — will not. They will move on. And the next wave coming in for Noah will be younger with different viewing habits. They will not watch the traditional way. They will, at minimum, time-shift. And until they adore Noah the way Stewart's core base adored him, they will not make a nightly appointment with the show in the way that Comedy Central is used to. Those are two immediate and dangerous problems.

It's much more likely that new fans of Noah's Daily Show, after the dust settles, will watch selected bits of the show online. Ratings will decline — over time, probably steeply. This is not an issue of Noah's character — something this Los Angeles comedy performance and TCA visit neatly alleviated. This is old model vs. new model, not old host vs. new host. It's not Noah's fault that the traditional model is how Comedy Central makes its money. That's an industry-wide problem, which means Comedy Central will be dealing with the same issue that NBC (Fallon and Seth Meyers), CBS (James Corden and Colbert), ABC (Kimmel) and TBS (Conan O'Brien) are dealing with: how to monetize a large portion of the audience that only wants to watch the best bits of the previous night's show online.

The scary thing for Comedy Central to embrace right now in this intersection of change is that its late night success began 16 years ago in a different era, when the available audience was looking for different alternatives participating in the same model. They found those alternatives in Stewart, who made The Daily Show what it is, and they found it not much later in Colbert — two men who each generated a cult of personality and who have and will be walking out the door, taking those cults with them.

That is the stark reality. Noah's audience will by and large not be participating in the same model. Thus, this really isn't about Noah at all.

In fact, Stewart's retirement is really more about John Oliver than Noah. Oliver and HBO are the probable winners here. Stewart's core fans obviously would prefer more years of Stewart in the Daily Show chair. Lacking that, his audience and the demographic it represents more feasibly shifts to HBO (and pays for it if they're not already) and Last Week Tonight. It's a perfect match of audience age, host style and model.

What's devastating for Comedy Central is that its forward thinking might have found the right man for the future but it operates in the present, in a model not built for the audience of the future.

Email: Tim.Goodman@THR.com

Twitter: @BastardMachine