I meant more that them being top dog in MP isn't a guaranteed money-spinner.
They've never really been top dog in MP games (maybe early CS, before China & online consoles became a real thing) - even with CSGO and Dota2 at their peak numbers. Other games (outside of Steam) have (and are) bigger and earned more revenue, doesn't mean CSGO and Dota2 don't earn incredible amounts of money anyway.
The answer to one or both of their MP games gradually losing popularity wouldn't be to go back to single player games, it'd be to either:
A) Find ways to recapture people in those games
B) Make new MP games
There are few businesses out there that wouldn't love to be in the position Valve are in in regards to their ability to create and maintain incredibly successful MP games. Valve have that competitive advantage and they'll keep using it for as long as they have it. Many companies try to make their own Dota2, or CSGO or even the less successful TF2, but they can't do it. It's far from easy - few ever approach this success. These games are lower risk, they generate a load more money and in general have a huge amount more potential to last for a long time after release (again, generating far more revenue over the life time of the game).
Valve could try and release two or three brand new MP games on the scale of CSGO or Dota2 and still not approach the risk of a big new AAA single player game. Risk isn't just about earning development costs back, because we know HL3 would easily do that, it's the risk of spending years on a game that'll fade out after a month or two, when with that same manpower and money you could throw some MP games at the wall that most likely would last a lot longer.
Edit: Forgot this was a PUBG thread. This Valve stuff shouldn't really be derailing it..
