Follow them where? The only other large streaming service anyone cares about is Twitch, a service often just as bad as Youtube. Trying to get several hundreds of thousands of followers to move to any of the smaller platforms, many of which probably aren't even equipped to handle it, is incredibly unrealistic.
You don't seem to understand that 99% of Hololive(or any channels, actually) audience only discover them because they already use Youtube before. If they are to move to a theoretically "better but smaller" platform, then they're basically shutting themselves from getting any newer audiences, and that's not even discussing the fact if such platform with less issues exist or can be trusted to remain functional in like, 3 years from now.
