What Happened to Pokémon Go?

Issues at the peak of popularity caused people to abandon it. Once they abandoned, they never came back.

1) Servers were swamped and had difficulty scaling to match performance to users resulting in downtime.

2) Not enough skill curving, it made being a casual very difficult because you would get stomped in gyms/battles.

3) Not enough mitigation against GPS spoofing/cheating further killed the incentive for casuals.

4) Over-monetization resulted in pay-to-win conditions.

My wife still plays but I got overwhelmed by the sheer number of pokemon that exist now.