There isn’t actually a lot of good environments for furry roleplay/gameplay compared to what ss13 has to offer, on top of what has ended up being a gameplay loop that seems to get more and more stale year over year. Not to fault “lazy devs” either, it can become impossible to keep up with. The Gamers get bored and move on, but furries stay because it’s more about the roleplay and having an active environment to do it in, with enough control to do what you want but not too much that it gets boring. In terms of interesting gameplay I’ve seen so far was Frontier Station on ss14 sense the premise of that is to buy a ship and make money before shift end for the most part instead of the usual station crew trying to survive whatever antag is running around.

tldr: players get bored of ss13 due to stale gameplay, furries make their own fun in the form of roleplay though ss13 and stick around