First of all, plenty of people would be happy to self-host a game for their friends, if they were still allowed the option.
Exactly! Me and my friends often play on modded Factorio servers that one of us hosts. This is only possible because the developer doesn't lock things down to only the first-party (official) servers.
We don't play with cheaters either (you aren't getting invited to our server if you are). We play with our friends because it is fun, in a way no official server could hope to work.
Exactly, every time I say 'I'm thinking of putting up a Factorio server, you want in?', they are significantly less likely to be playing (or paying for) the newest game that has kernel-level access. Why, because we are playing Factorio for the next few weeks together and Factorio is fun.
Factorio isn't the only game we play, but the point is to reinforce yours. If you are playing fun game x, your friends are more likely to play x instead of something else. Even if they have no care about Kernel-Level access, the fact you do affects their buying (and playing) patterns.