Because I've built up a presence over 10 years of running the site, so, I'm not just about to move! It'd be a huge pain to move probably hundreds of email addresses over to a new domain etc too (I sign up with [domain]@snowpool.org)

It completely depends on what they do, I've renewed for 10 years so I have time now, if they put the fees to >500 a year then I'll definitely move.

Do you own a domain yourself that people have been using for 10 years? You might feel differently about the ease of "just moving"