One doesn't even need monopoly either, just a strong enough leverage against your customers. See Oracles.

It doesn't matter if there's competition at the customer acquisition stage, as long as there's some form of customer lock-in the corporation is going to abuse them somehow.

And companies without some kind of lock-in never scale in the first place, and that's why we must face this kind of bullshit pretty much everywhere even from companies operating in competitive markets.