"tend"
I dont even know you lmao.
Megas are not gonna be debuting in gen 7, and the most popular picks are largely gone; anybody thinkng we will get the same ammount of megas as XY are just being.... Flat-out wrong.
Like I've said before, there are tons of Popular picks still remaining in Sinnoh, Unova, and Kalos.
Not to mention we've still got some popular picks in the past regions as well.
And like Aromatic Mist mentioned, not all of them need to be popular picks. Considering we're getting a brand new gen, it's very likely we'll be getting the same amount X/Y did, if not more or slightly less.
I mean, they didn't even need to make more Megas in ORAS besides the starters, and look at what they did there.
There's some like: Dragonite, Snorlax, Lapras, Butterfree, Slowking, Johto Starters, Flygon, Milotic, Froslass, Hydreigon, Chandelure, and a few from Kalos.
Those are some of the popular ones I could think of that can get Megas, and the three whose counterparts received Megas in ORAS.