It's no secret that Pokémon GO is popular. But that doesn't always mean that a product is lucrative, especially in the case of free-to-play games.
But Niantic was very careful in how it delivered microtransactions in Pokémon GO. Lucky Eggs aren't mandatory, but are the fastest way to level up. Poké Balls can be acquired for free, but it's hard to keep up stock over time as Pokémon become more difficult to catch. Attractive pokemon are rare, pushing players to buy Incense and Lure Modules. As a result of this, Pokémon GO is already one of the most profitable mobile games in history.
Sensor Tower reports that Pokémon GO has surpassed $200 million in revenue within one month of release. This is nearly twice as much as Clash Royale made in the same amount of time, another popular mobile title.
Niantic has recently begun communicating with its player base, while its server infrastructure has become more resilient. Due to this, it should see well-sustained popularity following its explosive first month.