Wow that is tiny thrall limits for some private servers.
Below is what I do on my private run (3) servers and has no relations to the Official Server discussion in this thread.
I have not check the limit on the server I play on occasionally, but I have a limit of 300 on my servers. 50 +25 (although no clan is at 10 players) Most clans are 3 or below so the cap would be up to 125. I put the cap in 2019 to give flexibility for players/clans and never thought it about it since.
I also allow players to build up to 25k. All the clans beyond my clan is below 12k. Majority below 5k. So buildings has not been an issue. My clan also has many server built locations that includes a testing area for people to view modded / vanilla / dlc structures so overall the clan exceeds 33k. Advantages of being owner of the server. (Gportal servers)
The largest clan of 9 had 93 thralls / pets. My clan (with admins included) has 8 members and 91 thralls / pets. The next highest clan is 4 members with larger number of followers has 96 thralls / pets (odd the smaller clan has more than 2 biggest ones). Overall, most clans have very few followers numbering 20 and less.
Nice thing about private servers, the server owners make those decisions on what they think is best.
I did have a wipe in 2019 but it was due to a bugged mod crafting station which was not known at the time of the cause of the server instability. Players voted for the wipe. Although the players who voted for the wipe most ended up stop playing and I had a new set of players. Odd how that worked.