I don't give a shit. I use substack because I don't want to use a private domain for what I wrote on substack.

My private domains I self hosted on my own servers, but those are used for private stuff.

Substack is good for public stuff. If they shut it down I don"t give a shit. I have backups anyways.

Well if you're not going to self host or keep back ups and have a tier for the more racey content that's the risk you run. People use these services not only because they're easy to use but because these are brands with a network effect, if you want to use a service you have to play by their rules, if not run your own

Best thing I ever did was move from Substack to Ghost 3 years ago.