Well...yes and no. If you are staying at AK and want to go to MK, you COULD drive there if you had your personal vehicle or a rental. But then, you would have to park at the MASSIVE MK parking lot, take a tram, then get on the ferry or monorail. On the other hand, you could board the bus at your resort and be dropped off pretty close to the gate and not have to remember where you parked your car and all that. Sure, it does take some time to get there, but just walking up to your resort line at the bus stop after a long, hot day is totally worth it...even if you have to wait for the second bus. Chatting with others waiting is a good thing in my world. I love comparing notes about places to eat or what someone's favorite thing about a certain resort might be.
Disney is pretty clear about the "20 minute wait" thing. And I have been pretty p/o'd sometimes because of people that pull up at the last minute to the handicapped spots that result in me....that has been waiting 20 minutes already for a bus and can't get on that bus because of this last minute person and their entourage...not being able to get on the bus. It is probably cost prohibitive, but there should be some kind of "wait your turn" type of thing at busy bus stops.