Social accounts are monetizable & part of peoples brands now - “well if it blows up ah well” might be fine for you or for me, but might not be for others.
Arguably we’re seeing the beginning of Twitter blowing up and if that falls to Digg-like irrelevance they face a similar issue.
Then don't use free instances? There's a bunch of companies that would run a dedicated instance for you for a couple dozen $/mo.
Less than that. Weingärtner is 4€/month for an instance they say is suitable for up to 5 users. Masto.host is $6 for the same. This is a major advantage over centralized social media in terms of platform risk.