>If you can be considered a monopolist because you control your platform then there will be a LOT of monopolies out there.

I think there's a fairly trivial distinction to be drawn between a general purpose computing device and a utility like a fridge or a car. (something like, is the system aided by software to operate, vs is the system a platform for executing user-software)

For something like a game console it might actually be an interesting edge case but it doesn't seem difficult to draw an approximate line.