1: Blame the DL's even though it may or may not of been their fault
2: They dead
3: Cause a lot of people are like "let's play CS:GO jailbreak" populating it to like 10 people, then leave in less than 5 mins because they want to play some irrelevant game, making the people in there leave, because there are almost no people on the server anymore D:
4: Because Trade servers OP and probably due to F2P (not sure tho)
5: Because they probably think it doesn't need improving, which it obviously does.
6: l4d is kinda of a meh game (doesn't catch my attention at least)
7: Blame the person who is suppose to do it
8: When the servers went to shit
9: Because deep inside you want it to be back the way it was, but most likely wont