Wrong. Mythic+ is NOT the same this xpac as the last two. The gear previously from +15's would be the equivalent of Heroic warforged with a mythic piece in your weekly chest. The gear that currently drops from mythic+ is 100% useless for ANYBODY in 213+ loot with the exception of the weekly vault. So no...mythic+ does NOT make up for lack of loot in raid like it used to. Hell, in Bfa you could already outgear a heroic raid by its second week because of mythic+ loot at the end of the dungeon. Doesn't work that way anymore. So heroic+ raiders do not have mythic+ to get those "extra pieces".
The reason they did what they did with loot is in bfa loot was everywhere...and they wanted loot to have some meaning once you got it. But what they forgot to do was to make the loot that did drop...interesting like it used to be. And they ended up nerfing covenants into something much MUCH weaker that what it originally was.
Loot in raid right now is just too scarce. Too many times have I come out with absolutely nothing.