Though Pokémon GO's audience has dwindled a bit since its launch (nobody wants to go hunting for Pikachu while sloshing knee-deep through slush), it's still amongst the top ten grossing apps on the App Store.
Pokémon GO could arguably make tons more money if it was released in China – but that won't be happening in any official capacity any time soon. The state cites "a high level of responsibility to national security and the safety of people's lives and property" as a reason for disallowing Niantic's app on Chinese soil.
According to Reuters, a games panel of the China Audio-video and Digital Publishing Association (which is governed by the State Administration of Press, Publication, Radio, Film and Television censor body) also mentions the "threat to geographical information security and the threat to transport and the personal safety of consumers" on its website.
Pokémon GO has indeed been a catalyst for traffic accidents and trespassing charges, but the app's reliance on Google Maps is the bigger reason Pokémon GO won't hit China any time soon. Google Maps is blocked in the country (some travellers report getting Maps to work in China, albeit in a very limited capacity), and augmented reality games like Pokémon GO depend on Google Maps for its world-building.
China isn't completely devoid of Pokémon goodness, though: The launch of last year's Pokémon Sun and Moon for the Nintendo 3DS marked the first time Pokémon games received an official Chinese release.