It did change a lot but the biggest changes were the ToS/AuP of server/VM providers. What was not even taboo in the early 00's was becoming a problem keeping an account active on clear-web sites. Across the board many providers starting using the vague word "lewd" a word I had never heard of even after running porn sites for a long time.
Many of us moved to .onion despite being incredibly slow at the time. We would keep an unpublished clear-web sub-domain active for the old time users so they had a fast connection. Eventually that was even problematic so many forum operators stopped accepting new users and made their forums private or semi-private. Some still exist and some got married, had kids and real life took too much time and energy to also run such sites.
They complain about hiring a moderation team to respond to abuse reports? How are they doing it now? Do they not respond?
Gone are the says of paying a couple hundred a year for a host and a vBulletin license. The new costs are many thousands plus permanent liability, and no thanks - that's way more than I'm going to do for a group of enthusiasts online.