I'd like to see your math, as it isn't just the loading of passengers that takes time. It would seem that slowing down, completely stopping, lowering the bus, opening the doors, and then closing the doors takes up at least some of the time at each bus stop.
(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.
The counterpoint is any bus route that has an express option that runs in parallel. Every time I have taken the express route, the bus can be full to the gills, but is always faster than the non-express bus.
surely we can think more critically than this...