Ingress' backstory is a garbled mess of stupidity. Nobody, and I mean nobody, actually gives a flying fuck about the whole XM and enlightened vs resistance lore. That game was successful because people enjoyed the mechanical aspects of it, but, that's all it had. It was visually boring without the lore or hype to support it if you didn't truly enjoy the setup.
Sure, Go is just a total re-skin without really any reinventing the wheel in terms of mechanics. So what? Ingress was fine on mechanics. It gives appeal to kids, a FAR more established backstory that people were already invested in before release, a better motivator to keep playing (catch em all), with very evident future additions already in store such as battling, trading, and new pokemon.
Any free to play mobile game is going to fade after release. There's a huge gap between the game losing its launch week hype and it being a dead fad. I can't imagine the cash cow of this game being dropped. They already have anomaly infrastructure to just port in as rare/legendary pokemon at whatever degree of releases they want. Sure, yes, the frantic hustle and bustle dies out, but people keep the game and still check in when they walk around. Everything they need to just keep people on their leash and coming back every now and again is right there. It was there for Ingress but all they really needed was an actual base they never bothered to make any decent. It just happened to be Pok?mon. it could have been Mario Go or Transformers Go or SpongeBob Go but alas it's Pok?mon. Shame I never played past red.
