And let's not forget that driving tests are not standardised in the US amongst states. So depending on where you live, your test could either have been something that really checks if you know how your car works, how to safely do maneuvers, how to react to emergencies and how to drive with other cars on the road, or it might have just checked that you can drive around a block. Fix your driving licence tests at a national level, then maybe you'll see how the DMV is useful.
...but that's not how it is now, so I agree that right now, the DMV mostly exists to collect tax on vehicle registrations, license fees, title transfers, and other annoying paperwork-heavy things. The smog test industry is pretty scammy (you can find "a guy who knows a guy" who can get your unable-to-pass vehicle's paperwork done with little effort) and the license stuff could be handled online in conjunction with drivers Ed schools (since IIRC you have to take classes before you can take the test anyway).
And let's not forget that driving tests are not standardised in the US amongst states. So depending on where you live, your test could either have been something that really checks if you know how your car works, how to safely do maneuvers, how to react to emergencies and how to drive with other cars on the road, or it might have just checked that you can drive around a block. Fix your driving licence tests at a national level, then maybe you'll see how the DMV is useful.