I guarantee it still takes more time to drive yourself almost every time. Buses come within 10min almost always.
YMMV--the worst bussing we had was when we stayed at Coronado Springs. Despite having those lovely boards up telling you when your bus was supposed to be arriving, and the board said "bus arriving", they never showed at our stop! We waited over 45 minutes before we hiked it to another stop. Most ridiculous thing. EVER! That's when we said "absolutely no more buses" and started renting cars only. And when WDW started charging to park your cars at the resort (biggest cash grab ever, imo), we started just renting DVC point rather than getting 2 rooms. Cost less in the long run and easier to get groceries ourselves and bring them back to the room.
Our primary reason for renting a car, besides being able to get to dining reservations at other parks faster than doing a bus shuffle, is that I have very impaired standing balance. And at the end of the day, trying to get a seat when you don't have a "visible disability" is next to impossible. It's much easier, and safer, for me, to be able to ride sitting, with a seatbelt, than try to stand for a 30+ minute, crowded ride back to the resort. And with DH's corporate rates, doesn't cost us very much. By the time we would pay for all the Uber/Lyfts, we break even and can get ourselves to the airport when WE want to leave, not the crazy ME timeframes, still utilizing the bag checks at the resort (when they still were using them).
I will admit, that back in the early-mid 2000s, the buses were great! That was one of the things we really
loved about WDW--all the free transportation! When DH and I went in the early 2000s (like 2002/2003 our first time as a married couple), we stayed off-site, and seeing all the free transportation options (I had done ZERO research) convinced us to always stay onsite--ok, that didn't
always work when bringing large group of family down). But it is nice to know that as our teens want to sleep in, the buses are there to get them to the parks to meet us and we don't have to go back to get them. They just don't work
well for me, personally.