You would stop getting updates (and upgrades). It would be theoretically possible to update your OS and break compatibility. I think it's best to maintain support starting at $99/yr because you not only get updates, you'd get upgrades which some would consider a great value at that price and, of course, you still can get support which can be important. I do know of people who will "freeze" their system (OS, drivers, etc.) when support ends to ensure the compatible state remains.