It isn't really that fair, the critical time sink starts shifting to offload/onload time and there is a lot of waste having to load each bus individually.

This is why developed subway systems with high usage end up with large trains, that's the best way to speed up the system, reducing the delay caused by trains waiting for other trains that are stopped in the station.

Even a "train" of two buses is impractical for most bus routes because of the weight, poor turning radius and so on. I'm pretty sure going any longer than two is virtually impossible.