Different - the objective of EEE is to kill an opponent. The objective of PSS is to maximize the profitability of a product at the expense of the customer. It's really nothing new, this is how every business works - but this force is supposed to be tempered by the existence of competitors, who will take your customers away if you drop the quality of your products too low. In monopoly scenarios, there is nothing to stop a runaway squeeze.

All the corporations accused of acting this way are network-effect quasi-monopolies. That's the root cause.