Two years ago today, a studio called Niantic released a game with a novel proposition: Go outside. Point your smartphone at the real world. Catch some monsters. Within a day, Pokémon Go was at the top of every app store chart. Within 200 days, players had spent a billion dollars on in-game upgrades—the shortest time to reach that milestone by a wide margin. In the summer of 2016, you couldn’t walk two blocks without running into, sometimes literally, a person in hot Pidgey pursuit. And then it stopped. Or so it seemed.

The news reports faded. Shops that had seen a sharp spike in sales thanks to Pokémon hot spots settled back into their normal routines. In just four weeks, between that August and September 2016, Pokémon Go shed nearly 20 million players, as enthusiasts headed back to school, or lost themselves in various other viral pursuits.

But the game’s long retreat from that initial burst belies its continued, unprecedented success. And in the gap between what you might think happened to Pokémon Go and the game’s current-day dominance lies an important lesson about the future of apps.

Pokémon Went

It’s true that far fewer people play Pokémon Go today than did two years ago. In July 2016, the crush of players boosted attendance at Pokémon-heavy Crystal Bridges Museum in Fayetteville, Arkansas by 50 percent year over year. By that August, the tide was already ebbing. “It seems like the hype died down in the span of a month,” says Crystal Bridges public relations director Beth Bobbitt. (She adds, “We still have a lot of ‘pokestops’ and ‘gyms’ all around the museum campus so I think we’re still a great location to play the game, for those who still are.")

'You’re forming real friendships with them. Friendships are sticky. That’s probably the secret sauce of the game, right there.' Niantic CEO John Hanke

You’ve seen this yourself, anecdotally. There are no viral videos of Pokécrowds gone amuck anymore. No one makes Weedle jokes at the water cooler. The natural conclusion: Pokémon Go is just another fad that disappeared in a blink, a fameball of Pog proportions. But writing off Pokémon Go after the initial frenzy is like assuming PyeongChang no longer exists post-Olympics. What matters isn’t how Pokémon Go looked at its zenith, but how it held on from there.

“It was completely uncharted territory. The initial fervor, that global excitement around the game and the way it spread virally, globally, in such a short period of time. It was a new experience for all of us,” says Niantic CEO John Hanke. “But looking at it in retrospect, it looks very similar to all games. There’s an attrition curve that’s reasonably consistent across games. Some games are better at that attrition curve than others. That kind of separates the winners from the losers.”

By every measure that matters, Pokémon Go has been a winner. Since its launch, it has almost never dropped out of the daily top 100 downloaded apps in both the iOS App Store and the Google Play Store, according to app analytics company App Annie. It has been the top-grossing app in the Play Store this entire week. In two years, according to an estimate by app analytics firm Apptopia, it has taken in $1.8 billion in revenue.

"Even though the mega spending at the beginning has died off, the rate of revenue is still highly impressive," says Apptopia communications lead Adam Blacker. "Where the money comes from is actually pretty evenly split between iOS and Android, which is unusual"

It also helps that mobile games don’t necessarily require lots of players to be successful. Revenue generally comes from power users, the whales that invest in PokéCoins—or whatever their poison—the way others might their 401k.

“Generally speaking within games, a smaller portion of your users are spending a lot of money. That’s true of most premium games,” says App Annie analyst Lexi Sydow. “I would imagine that trend would hold for this game.”