Like Elesa, Skyla's design is certainly "hot" in the conventional sense, and I jerked it a few times to her during the BW era, but it doesn't have that special "semen demon attribute" that makes Skyla a timeless waifu like Sabrina, Mallow, Morrigan, Tifa Lockheart, Etna from Disgaea, or most of the Gen 7 girls.
Once BW era ended most people (including myself) forgot about Skyla and Elesa cause they are "just hot" without that "special timeless attribute" that Game Freak is so good at including in their female characters. It's the same thing that keeps people talking about girls from older gens like Misty, Sabrina, May, Dawn, Rosa etc. Without it, you just get a bunch of dudes cumming at your visage for the duration of that respective Gen, then everyone forgets about you, including artists. This is just my opinion tho. Sorry if i'm not really making sense. Skyla just kind of "exists". It also would've helped if Gym Leaders got more than a few line of dialogue before fucking off for the rest of the game, to make them more memorable. Gen 8 should be a waifu simulator with relationship building