While it was popular, it wasn't as popular as Flygon.
It was the 6th movie which boosted the popularity of Absol and Flygon, but Flygon go more focus because of it temporarily teaming with Ash in the Movie.
And, considering that they gave Goh the Absol in the recent episode, and also the fact that out of all of Ash's Pokemon until now, his Fighting type (aka., Farfetch'd/Sirfetch'd) knows the most variety of Dark type moves. I think, the writers might be planning on skipping Dark types on Ash again (or atleast skipping Dark types that can use Dark type moves).
It's more "super popular Pokemon in general" than "Pokemon fans have specifically wanted Satoshi to get. All those three are enormously popular.
Well, i agree on that.
But its kind of odd though, because in terms of "popularity", isn't Flygon supposed to be more popular than Dragonite?
Atleast that had been the case since 3rd Gen, and how many people have been complaining on Flygon not getting a Mega during 6th Gen, and even the Creators had to reply on that, because of multiple questions from Fan about it (but there was no mention of a complain relating to Dragonite not getting one).
While they did give Flygon to Goh, but it really isn't that special, considering he catches a lot of Pokemon in general.
And "rumors" tend to tun out false because "rumors" tend to just be someone making crap up and saying "dude trust me". Why do you even acknowledge them? Anyone can make something up and call it a rumor.
Well, i don't really acknowledge a rumor normally.
Just said it because i thought that maybe the "Toxel/Toxtricity" for Ash ship had long sailed, and no one expect it to happen (like with the recent "Kubfu for Ash" one).