The concept of "flash in the pan" has been around a long time.

That said, PoGo is tapping into a very large and well-established fan base with literally decades of interaction behind it. Those fans have been willing to pile onto most of the offerings in the franchise. Separating that out from the first-mover advantage that PoGo has (and its predecessors, including Ingress) failed to capture would be a neat trick.