Why is it, then, that services seem to trend towards all-you-can-use at a flat rate? Even when there are lower levels of service (in whatever), they're usually

Why is it, then, that services seem to trend towards all-you-can-use at a flat rate? Even when there are lower levels of service (in whatever), they're usually ridiculously less service for a bit less price, which seems to just be a way to drive people to the One True Price that the provider really wants.