Counter-Strike 1.6 is an ancient game, older than AH3, but it has enjoyed a new lease of life in Eastern Europe and China.
It's simply a question of marketing and making it accessible.
Old games can be very inaccessilble to new players. Matching novices against people who've been playing for years. The older players sometimes fail to recognize they might have to choose sometimes between playing and winning, or at least playing fairly. In AH3 I don't think that is so much of a problem, I managed to do alright on a clapped out computer with no experience.
This game has a lot of information which is not immediately obvious to a brand new player.
Counter-Strike did so well in Eastern Europe and the Far East because there is not a lot people need to know to match experienced players.
Few thoughts there, food for though.