So what has actually been established?
Different people like different bikes for different stuff.
All mountain 26ers are better than xc 29er for riding steep rock downhill – no great surprise.
People who don’t have both are staunchly against what they don’t have.
There is some sense on Stw!! Shock horror.
The comparison between similar bikes 29 and 26 is proving to be a challenge but from another thread taller people may well prefer or find it easier to get along with bigger wheels especially on rolling or downhill type terrain.
People who came from bmx might find smaller wheels preferable. And those from the road may prefer bigger wheels.
That’s it. Buy a bike, ride, brag and evangelise as much as you like. That’s what forums are for.
IMHO 29er all the way!