There is no assumption here other than yours as my experience in quickplay lines up with what jeff says.
My original assumption matched what you said, back when I first saw Kaplan’s post on the subject. It wasn’t until I saw it disproved first hand (or rather, clarified to not apply in Arcade) that I learned otherwise.
I feel like that queue thing only happens when you select the same game mode. Leaving quick play just after the victory is decided and queueing up a game of mystery heroes, I’ll find myself instantly getting into a game, well before that other match would have went through all the player cards, replay, etc.
Fine, think whatever you want. Jeff says you’re wrong and I say you’re wrong so 2 to 1 you lose.
Somehow that transformed from “He doesn’t mention anything about it” to “He says you’re wrong” from one post to the next. 
But yeah, there’s obviously no way to know for sure until you see it happen, and I don’t think I’ve saved any clips of it, so not much point in arguing further.
I stay for the end of match stuff unless it was a blowout or backfill in which case I will leave at the POTG since it didnt really mean anything to me.
I was aware of the delay when quitting early but sometimes its better than getting the match rubbed in your face. 