If it is trivial why do they put so much effort into squishing it?
Did you ever consider it in terms of strategy? Companies try to use strategy instead of lazily waiting until the last minute to passively react the way so many individuals do.
It's trivial now but that could change. They are taking steps to keep it trivial and/or to make it more so. If they neglected it entirely, it might become a very large, entrenched, difficult-to-eliminate market by the time they get around to reacting to it. What would really entrench a used-games market with no artificial restrictions? That's easy: for it to be common and perceived as normal by the average customer, something they come to expect, something they would be outraged about if it were taken away.
The game companies don't want that to happen. They're smart, so they think of these things ahead of time. They're greedy control freaks, but they're not stupid.
Do yourself a favor and apply this strategic view to every action corporations and politicians take and to every word they say. The world will become mostly predictable then.