Its not true. A fragmented playerbase hurts everyone. I was there in the Source vs CS 1.6 days. Source and 1.6 were basically completely seperate communities, which were only really unified when CS:GO came out.

Imagine getting the new CS only to find out all your friends refuse to move to the new game, so you have to go there too if you want to play with them and learn everything anew just when you learned the ropes in the new game. A terrible new user experience, which hampers growth, which leads to a dying game.

Updating a hugely successful game is always difficult. Should you cater to the "old guard"? Absolutely. But when they are a contentious bunch who hate change, you just have to force them, or they will paint themselves into a corner, completely isolating themselves from new players. They would probably see this as a win too: no annoying "n00bs".

This would be exactly the situation that developed between 1.6 and Source.