I think it's too early to know what Twitter's trajectory is. I'm not an Elon Musk expert by any means, but his actions related to Twitter seem erratic.
He successfully bought Twitter for more than it was probably worth. (Apparently, publications that track people's net worth dropped his by 10 billion after the sale went through.) But before the sale went through, Musk tried very strenuously to get out of it, resulting in a long and PR-nightmarish public legal battle--which Musk lost. End result--before Musk walks in the door, he's perceived as the CEO who doesn't really want to be there.
Almost immediately, he fires more than half the staff--3700 out of 7000. (By the way, I'm not sure how Luke--or any of us--could know from the outside what the fired folks were like or whether or not they were essential to the business.) Then he fires more. Since Twitter was in financial trouble, I can easily understand the need to try to figure out ways to downsize, but I don't know how Musk--who, keep in mind, claimed the information Twitter was providing him wasn't accurate--would have known who and what to cut. The fact that he was very quickly fishing for coders leads me to think he may have cut too deeply.
Oh, and then he even fires people who'd committed to his vision of Twitter 2.0. The vision involves working harder and longer. Because asking people to work longer hours, presumably for the same pay, is a guaranteed recipe for success. Meanwhile, Twitter is losing more staff because people amazingly enough resigned in large numbers also.
Some businesses have indeed been reorganized on day 1 of new ownership, but the success of such moves presupposes that Musk had spent a long time--in between planning legal strategies to get out of the deal--figuring out what needed to change. The visible evidence suggests otherwise.
Take Twitter's moderation policy as an example. Musk was initially committed to more or less unlimited free speech, with a stated intent to ban only accounts that were spamming or fraudulent. A wave of people using the n-word in their tweets (one of the factors in getting advertisers to pull out) caused him to reconsider. (As if it shouldn't have been obvious from the beginning that something like that would happen.)
Consider the case of the Donald Trump ban (offered as an example of Musk's indecision, not as anything political). Musk announces in advance that he will rescind Trump's ban. Trump says he won't come back, anyway. Musk says maybe he won't reinstate him (which might have been a sensible reaction to Trump's ban, except for what followed). Then Musk says he might reinstate him, but only after the content moderation team is in place. Then Musk says, "Oh, what the heck. Forget the moderation team. Let's just take a poll of Twitter users." The poll favors Trump. Musk reinstates Trump. Trump reiterates that he isn't coming back. Of course, he may change his mind, but even if he does, what about this progression suggests that Musk has anything remotely resembling a coherent plan in place? To me, it looks a lot like make it up as you go along.
Keep in mind that this is the same Musk who announced in the first day or so of owning Twitter that it might go bankrupt. Why shouldn't we fear Twitter's solvency when the CEO is telling us Twitter may not be solvent? I imagine he said that partly to justify his actions, but it's still not a good look for someone trying to convince stakeholders that he knows what he's doing.
If this really is a temporary state, then yes, the advertisers will come back. But until Musk starts acting like he actually knows what he's doing with Twitter, I doubt that's going to happen. And whatever arguments can be made about free speech and online forums, most major brand advertisers are not going to want to advertise on what even Musk at one point (I think right after the n-word debacle) seemed to suggest would be a hellscape without moderation.
Did I mention the sudden disfunction of Twitter's copyright protection system and whole movies getting uploaded? Because that's not going to win back big brands, either.
All of that said, I ironically agree with Luke that there's no reason for authors to leave the platform if they get good results on it. Anyone can always pull out later if (as I suspect), the platform goes into free fall.