M+ loot has traditionally been far more lucrative than normal and heroic raiding. It’s easier and it rewards failure. It’s only 5 people and requires far less organisation. It’s infinitely spammable.
But you only have to hint at the possibility of altering the loot so it matches the difficulty and M+ players go bananas - telling everyone else if they don’t like it they should just run M+ to get the loot.
Because in literally every single M+ thread you see the same arguments.
Here, have a read through this thread that’s remained active for 6 years: Bring back 5mans