Up until the point where the game was released in Japan, Pokémon Go was "only" slightly ahead of Clash Royale in terms of mindblowing success upon release. Then, 18 days after the initial release, it was brought to new levels, once the game reached its homeland and achieved global (almost) penetration.
Since then the things have continued full steam ahead, and it's estimated that Pokémon Go earned over $200 million in its first month! That's almost twice what Clash Royale made in the same period ($120 million is still pretty damn good) and well ahead of Candy Crush Soda Saga.
Additionally, Sensor Tower rapports that average daily playtime is keeping steady at 26 minutes, with no sign of it starting to decline. It's probably safe to say that the phenomenon will last for quite a while.