As a old SC2 player (since I got it after four year release), even if I haven’t played in a while (due to university), I think the game is old enough to make it free to play, that’s what I thought about Blizzard movement.
The game isn’t dead, it has awesome campaigns, a great arcade (like mod workshop) support, a great ladder system and lot of improvement that make this game so competitive and entertainment, so don’t make those statements if you don’t know nothing about the game. The whole game has a huge player database that switch between SC I and II, Diablo, Overwatch, WoW games, so free to play is another key to encourage more people to play and enjoy this wonderful game.