Maybe the loss of Twitter as a platform for social media self-promotion would be more significant than the direct effects of 2300 people suddenly on the job market?
Conversely, other platforms have already come along that target some of Twitter's use-cases and offered better UX and user engagement. I'm sure they, or a new player, could fill the void (successfully).
This is also less of a problem today (as opposed to years ago) when everyone with a meaningful social presence cross-posts or maintains a split presence on multiple platforms.
