A monopoly is a monopoly. Just because Steam is a good store today doesn’t mean they deserve to hold a monopoly over the pc gaming market. So what happens when Valve has crushed every competitor? Gamers and devs have nowhere to go if Steam turns to shit. Eventually there will be a change of guards at Valve’s C-suite when Gaben retires or is dead. There is a good chance that those new execs will hollow out Steam and extract all the value out of it for their own benefit by screwing over the customers and developers. And they can get away with that if there is no competition. Competition is what keeps Valve in check.