Correction:Gen 1 and maybe gen 2 are really beloved.The rest is just grouped together.Just go out and see what are the usual pokemons that are used for marketing:Pikachu, Charizard, Eevee, Squirtle.And so on.Not only that, but only the mainline pokemon games sell well(and their remakes, which are based on mainline games).Most mario games, spin off or not, sell well.You get where I am going with this.
But Ill admit that pokemon is an oddity in the sense on how well it has survived without basically doing anything new.Its probably nostalgia mixed with the pleasure of capturing creatures, which Pokemon basically pioneered.And thats what makes me so sad that its stuck in the past.
Gen 3-Gen 7 have all sold 15-17 million, that doesnt happen unless it's a beloved series.
Also most Pokemon spinoffs sell well so I dont know what you're talking about there. Take a look at the game database.
When the herd loses its way, the shepard must kill the bull that leads them astray.