I understood the same thing Dave.... I think that the thread got hung up on what is considered a "Stem", which I agree is the summed busses or individual tracks that are not bussed.
So, to me, the DRUM MIX goes to a buss (that would be the drum stem). Vocals go to a buss (another stem). The guitars aren't bussed (each track would be a stem), etc. etc.
Technically speaking, with stems you could re mix the track but be limited in what processing you could add (control of the mix). I agree with you, if I was to send me work for someone else to mix, I would send each individual track (un processed) and let them have a go at it.
Jim