>>58703399First of all, this "shillmon" mindset has to die. Pokemon getting new forms aren't always determined by how marketable or popular they are. Otherwise, explain how Audino got a mega in Gen 6 or Garbodor got a gigantamax in Gen 8, two gens where Charizard was given preferential treatment? Meowth got two regional variants and it's one of the most recognizable pokemon in the series due to it's role as Pikachu's foil in the anime.
The logic is that Gamefreak picks and chooses what starter gets something in a legends game. Oshawott got a new form in PLA, so they wanted to continue the trend of Unova starters getting something in the next game. So, it was either Tepig or Snivy that was next in line. But considering that they wanted to use the rest of the Johto starters for the next game and that Legends Johto was scrapped for Kalos, Chikorita ended up being the grass starter of Z-A. Which means Snivy was out and thus, we were left with Tepig.
Whether you consider Hisuian Typhlosion to be a proper addition to the original or not, it's still one. It got something. After that, who else was there? Infernape's too soon because he just had a remake and gotten a new move, Raging Fury. Delphox was getting something regardless so it evens out, and Incineroar is in no dire need for anything atm. Better luck with Johto re-remakes, I guess?