-
Don't think it's that at all.
Historically, bike manufacturers don't have a big sway over the UCI. It's usually the UCI telling them what they can or can't do, and they have a long history of doing that. Suspending disc brakes is easy for them to do.
Reducing/managing motos is a lot harder. You'll need buy in from the race organisers, and historically the ASO don't get on with the UCI, with the ASO threatening to pull their races from the UCI World Tour in 2017.
I can imagine how well an edict from the UCI to the ASO limiting motos at their races would go down.
conspiracy theory coming through
It is interesting how abruptly and decisively the UCI responded to the disk brake debacle, completely unlike the lack of action around race convoy/ motos.
I think they saw it as a chance to suck attention away the moto problems, by coming down hard on disks sparking a long and tedious debate.