Doubtful.
Twitter will be there but, if you look at what sustains these companies is a mix of public buy-in as well as ROI. Public buy-in is the biggest component. If Doha-Kat or whatever her name is doesn't tweet, nobody logs on to Twitter to see what she is saying to her followers. No eye-balls; no advertising....no income.
Now, Facebook for a great example, became a must have in some circles because they offered something nobody else had...this virtual community to where you could share your experiences with people whom you already communicate; turning every move you make into a potential teleconference complete with original content, sourced media, etc... Before FB, YouTube was an innovator in that space except for the shared experiences....you could broadcast audio, video, third party media, etc... Then....boom.....TikTok supplanted them...so now Facebook has Reels through it's subsidiary Instagram to compete with TikTok. This is what a workplace does; they have the intellectual bandwidth to adapt to a changing marketplace.
Does Musk really think that these engineers who are looking to jump ship are chomping at the bit to work for a guy who just fired 1/2 of the staff of a social media giant? I grant that there is a strong mercenary culture in Silicon Valley but, unlike the mercenaries who read Soldier of Fortune, these folks can see the big picture.
Twitter will be around but to continue to get the buy-in; you have to offer something that is at least a few degrees outside of what everyone else is offering (which is why you see a new menu item launched every other week from McDonalds and whatnot). Its difficult to get the buy-in when you don't have the content and even harder still when your just fired your innovators.