I captured exactly 2 pokemons in Pokemon Go before deciding the gameplay was too shallow for me. If you had no childhood dream of filling your pokedex with pokemon the game has almost zero appeal.
Of course, lots of people HAD the childhood dream of filling their pokedex and endured the game for a bit but there is so much nostalgia google can do when the game has no gameplay AND no content.
One can just imagine what would happened if they had actually constant updates and some semblance of gameplay. Imagine a world where you could do normal battles (aka normal pokemon games) AND you had constant new pokemons to collect. The game could be huge.
But alas, it was not meant to be...