People are playing Ingress and Pokemon Go in Parallel. Both games use the same geo-located points and walk the same routes. They have the same places to farm and combat. I started playing Ingress again, but only a few minutes here and there. As I play I see new faces and new people at Ingress portals. They are no longer my age or older. They are much younger, in their teens.
There are a number of reasons which make Pokemon Go popular. I believe that the Ingress User base plays a key role, that marketing had an effect and that curiousity also played an important role.
Big user base Ingress has a large and vibrant community of players. These players are so passionate about this game that they are willing to walk 30 or more kilometres a day whilst staring at their phone.
My first thoughts on Pokemon Go are that we can level up fast. They have taken all of the Ingress Portals that Ingress players and I have created and turned them in to whatever the locations are called in Pokemon Go. I could research the names and terms but I am not that obsessive. Pokemon geeks can let me know in the comments. Is this why they stopped accepting new portals a year ago, to make porting the data from one server to the next easier?