Blizzard at some point publicly said that more than 60% of Starcraft 2 players never clicked on the "Multiplayer" button. This is why is has so much resources put into SP campaign with special units, recorded audio and cutscenes.

IMO this is why RTS genre really died out - the studios focused too much on eSport aspect and abandoned most of their paying customer base which wasn't interested in crazy clickathrons. Multiplayer games are very very loud, but they're not the ones paying most of the money.

When smaller studios tried to copy Starcraft 2, they usually cut down on singleplayer content and sales tanked with that.