Kanto will always be the most iconic and this will never change. I'm not trying to defend overshilling it, as the series is about variety, but kanto mons will be what the original fans signed up for and always be what normies associate it with. pokemania is a mythical part of history now but it was a big impression. the anime was best in kanto and the tone of the series set then may not be the most quintessential overall now, but will always be a pillar of what the series should look and feel like. the games got better each generation peaking at gen 5 then going down hill each gen. I'm not defending just giving the player a charizard or teaching the mechanics in a new gen with pidgey, but there will always be merch with pikachu, charizard and mewtwo, and if you want to represent the series in something like smash bros you shouldn't be cherry picking starters from random gens, you should use the iconic first gen, the "default" representations of starters, the "default" generational pikachu (pikachu himself), and maybe lucario for his impact even if he's not my cup of tea at all. incineroar and greninja shouldn't be there.
In conclusion, kanto is the face of the series and the original face of any series will almost always be the most iconic alongside any golden ages and renaissances. cope. however, being this series is about variety, the new mons should be pushed harder if anything because they need the marketing to even get noticed. hopefully the 2020s for media as a whole will quit the "90s nostalgia pandering" of the 2010s such as with something like sonic generations, and instead try to make new stuff that respects the old and uses the best ideas of the giants it stands on the shoulders of.