This "he isn't an idiot" or "not enough of an idiot" is the wrong way to think about things. Smart people believe all sorts of dumb things, and plenty of smart people can delude themselves, especially when they surround themselves with "yes men".

The other thing is X isn't the only social media platform, nor was ever a particularly large one as users go. Getting rid of Twitter just pushes people to threads, mastodon, bluesky and others. It doesn't actually shut down much speech at all.

I think the non-conspiracy thinking is just - Musk was addicted to twitter, liked saying edgy and engaging stuff and because of what was more of a boast but legally was a binding sort of offer to buy ended up forced to buy Twitter. The legal forces were well documented at the time. Now that Musk has Twitter, he decided to make it into what he always professed it should be, along with his egomania has made it more and more like any number of "free speech absolutest" spin offs that turned into right wing cesspools that regular people find less and less appealing, and advertisers really find concerning.