Yeah it's something I thought of years ago- when Blizzard started making bank, and they did, they could afford marketing (ugh) "Gurus" and the worst flavour of human; accountants. Suddenly the game wasn't made by gamers, it was made by metrics and bean counters. This is where we are right now, the victims of our own years of toil in the game have led us to create this beast that has studied us all in great detail and thus declares it knows what we want purely based on numbers. It's easy to see there's not a single shred of data thrown in that mix in regard to the average guild size and the average player in a raiding guild. Most friends from vanilla do M+ simply because in that narrow bandwidth of gameplay you are far more likely to play with friends (of what few are left) and not have to be at the mercy of noobs because try as you may, you don't get to spend time teaching them and they don't care to listen because they can simply drop out and find another group instantly.
Not a very good system for an MMO.