This will be an interesting experiment in large scale code rot. How long do you think twitter.com will work with the code base frozen?
I'm pretty sure that that's the plan Elon Musk is executing. It's simple, brutal, nasty, and probably not very well thought through. And yes he's not being very nice about it (to put it mildly). But it's not completely crazy if you can get over how obnoxious he's being.
He's clearly not interested in keeping the current team. He's never going to win them over at this point and from his point of view they were part of the problem, not the solution in any case. He bought a company that was basically not profitable, bleeding cash, and fresh out of ideas on how to fix any of that for many years. And he's now on the spot to keep that train wreck going. So, first order of business is to just cut the cost. That means decimating the team to a fraction of its size.
The Twitter team is basically rage quitting at this point so that's solved. Again, I don't like how he's doing it but undeniably, there are going to be vastly less people on the payroll very soon and cost will be a lot lower. The law suits that follow will be interesting though. But my guess is that he'll just buy those off and that will be it.
Of those that remain, he can cherry pick a team to salvage/build whatever he needs and then re-enforce it with some outsiders. Building a micro blogging platform is not rocket science and Elon Musk is actually deeply into rocket science. So, I actually get his gut feeling that this simply should not require thousands of engineers obsessing about all sorts of arcane software bits and pieces that somehow implement Twitter. It's a micro blogging platform with a fairly simplistic feature set. And he just called bullshit on how that was done at Twitter. And we're talking about a person with a long track record of having absolutely no tolerance for bull shit.
Again, not liking his methods but I can see his line of reasoning here. He has no respect for the Twitter team and he actually wants them gone. He wants to rebuild Twitter in a way that is cost effective and interesting to him. And he is not a risk averse person. So, in his mind that means a small team that can execute fast. I kind of agree with that part.
Will this work? I don't know. I see no technical reason that this plan could not work. But the big question is if the Twitter brand name will be worth anything by the time he's done or if he's just going to shut down the whole thing and walk away from it. He can certainly afford to do that. But letting this thing coast along just never was going to be a thing.