The major issue is the fact, that Valve never really did much for the game except revamp it.
1.6 was being kept alive because players wanted to play it - we had to figure out our own way of communicating via i.e. Ventrilo, pay for expensive servers, using mIRC to find matches etc. Even the majority of the map pool is based off of users contributing to the game. Source was pretty much the same thing. It's only now in CS GO, that you have Valve stepping in and being a relatively active part of the game in recent years. One can debate, however, if they are doing enough.
Also, major LAN's, online leagues etc. were so rough to establish, maintain and run, and all of these were solely carried out by dedicated players - Valve was far, far from it. And they haven't really carried the current events either. It's the organizers who are doing the work.