Twitter and Reddit CEOs having meltdowns affect more or less everybody who uses those platforms, don't they?

Not really. On many popular subs, most users seemed to be pissed off that mods were closing due to API calls blocking third-party apps. As for Twitter, those that just ignore Musk's antics probably haven't noticed a significant difference.

Learning how the Fediverse works is a small price to pay for a guarantee that their platform will never disappear out from under them again.

Many of these people have had accounts on these sites for over a decade, which is probably the longest account they've ever had outside of email. Nothing has changed for them.

Even if it did, people want to go where others are. No fediverse product has anywhere near enough people to make the switch worth it for anything outside of niche topics. Hell, even Threads is a bit empty for the average person, and most see it as a billionaire retaliation to Musk.

So yeah, a manufactured problem for the few.