(Bafflingly, they went through a transition period where ~all of the buses had two doors, but the driver rarely opened the back door. It wasn't really until covid that using the back door became standard. Improved things greatly.)
> and jockey for position and for a seat before the bus can start moving again
Do urban buses where you are require people to be seated? Didn't realise that was a thing anywhere. Any (urban, non-intercity) bus I've ever been on takes off as soon as the last person gets in.
My point is that you're totally disregarding everything a bus does to stop apart from waiting for passengers to board and de-board. At the very least it has to slow down, then accelerate. Half the time it has to swing the ramp out, which takes forever. Maybe someone has to load or unload a bike. Then it has to re-merge with traffic, and maybe every 10th car will let it in, so that can take a long time too. I don't even know if waiting for passengers is _half_ the time spent, let alone all of it.