The advertiser exodus is 100% a result of his policy changes and public persona. That’s just how it works, the advertisers don’t care about anything but brand awareness.
He changed policy, they left because that policy could be damaging to their brands.
But one of his policies was gutting the workforce, and despite all the dire predictions the platform has somehow still not exploded. There’s certainly a lot of reasons for that, and he’s been publicly embarrassed more than a few times, but if he’d gone in with a scalpel instead of a hatchet and not scared away the money and the tech it’s almost certain he could have made Twitter at least briefly profitable.
Twitter was losing money, but not by standards of potential and net valuation.
Put it like this.
In 2016, Twitter probably decided the US election. At the time, they had 3500 employees.
In 2021, they had 7500, and were losing less money.
Can you think of anything they did in that five year period that made you say, “Wow, that’s a good feature,” or “this community is amazing?”
Not really, right? It was the same Twitter, with double the workforce, doing not a whole lot with them.