(i know im very late) jokes aside, i think a large problem that leads to declining player counts is just that a lot of the gamemodes and features the servers utilize are just not nearly as popular as they were a couple of years ago. if you go and search jailbreak into the tf2 server browser for example, theres usually only 1-2 jailbreak servers that have any players at all out of the many jailbreak servers on tf2. Furthermore, one would expect trade servers to be dead as the tf2 economy is essentially dead. i understand that a lot of people on the server would just play deathmatch as opposed to just trading, but playing deathmatch on the exact same couple of maps most likely gets old, especially with trading being killed off. as previously mentioned in this thread, people also just grow up. sure, games like tf2 and cs have a decent amount of players, but not as much as they used to. people leave these games behind as they get older. you can (constructively) criticize staff but at the same time keep note that theres some things they cant fix regarding the servers.
sorry if i restated stuff already discussed, i didnt read every message in this thread