Most other series that just throw new mobs into the mix aren't highly multiplayer oriented though, so don't really need to give a shit about things like power creep or updating older entry enemies to maintain competitive relevance.
This is also one of the reasons Pokemon has stuck around as a brand where other imitators haven't. Like, a pokemon game might have a babbys first jrpg storyline to get through, but thats not really the gameplay hook, and fucking around with that doesn't really impact anything else.
Pokemons gameplay pillars are:
- Collect (literally the series tagline)
- Battle (the really quite complex underpinning strategic layer)
Its not laziness to not want to fuck with those core gameplay pillars any more than it is to not give Mario a gun, or make Mario Kart use more realistic vehicle physics and get rid of item boxes.
If you want a platformy third person shooter, you want ratchet and clank or Jak and Daxter, not Mario. If you want more realistic vehicle physics and a heavier reliance on pure driving skills, you want a Forza or a GT rather than a Mario Kart.
People who compare things like SMT or Digimon to Pokemon don't really want Pokemon, and that's fine. But the 'open world' Arceus has looks a lot like the 'open world' area that Sword and Shield have, and that whole area is fucking shit.