While there's something in that, Ryan, a fair bit of it is rather slanted.
Bayern, Real and Barca don't play in the Prem and a pound to a penny says they'd deploy a DM if they did; Matic wasn't ordinary that season, he was excellent, though the arrival of Kante has itself overshadowed him a bit; and Hendo and Can aren't more than competent at the role - on the contrary, they're less than competent at it at times. Can did well against Citeh last time out but hasn't generally impressed me in that position (he's far better unleashed to go forward and, for most of the season, has looked a victim of Molby Syndrome, i,e,teams playing attacking midfielders in more defensive roles just because they happen to be big units) and Hendo, while his distribution has come on by leaps and bounds, is rather less impressive at the yard dog part of the job.
Nor is it only at the back that the effects of a good DM would be felt. He'd also release the Cans of this world to do the essentially attacking job to which they're best suited. They'd still have to accept a share of tracking back, but I suspect they're actually more likely to do that effectively if they're spending most of their time doing what they actually do best.
We do of course need to improve between the sticks and in the back four, whether by replacing current players or by improving them (a lot). Without at least one class DM ahead of them, though, those improvements will get us only so far. The balance in the midfield just isn't right yet.