I went away for a short holiday with family this past weekend and didn't pay much attention to gaming news. Imagine my surprise, then, reading the headlines on Tuesday morning and finding that, by some measures the most insanely popular mobile game of all time , had already "lost its luster," as the headline from our own UK correspondent put it.

There's definitely some basis for such a summary. Pokémon Go has lost more than 12 million active users since its peak of just above 45 million in mid-July, according to Apptopia data summarized in a Bloomberg report. That month-long, roughly 25-percent drop from peak usage certainly sounds like the beginning of the end for what was recently an unquestionable phenomenon. Projecting things out linearly, you might even expect Pokémon Go to completely lose its user base by winter.

When you look at Pokémon Go's decline next to other mobile games, however, the expected drop-off in players doesn't look so dire or so surprising. While Pokémon Go's popularity peak might already be behind it, there's reason to believe the game's long tail can continue to attract millions (if not tens of millions) of loyal players for a long while.

The big drop-off

Back in those heady days of early July, it was easy to believe that Pokémon Go's stratospheric growth would last forever. But that was never realistic. After attracting so much attention so quickly,seemed destined to hit something of a saturation point with its potential market of players sooner rather than later.

This is in contrast to some viral mobile gaming hits of the past, which tended to start slowly and only reached their ultra-popular peaks many months after launch. Candy Crush Saga, for instance, only saw 10 million downloads in December 2012, shortly after its launch. The original Angry Birds took nine whole months to reach just 20 million downloads. Pokémon Go, on the other hand, saw an unprecedented 100 million downloads in its first month, according to estimates derived from App Annie.

With Pokémon Go's daily player numbers already declining, though, those light-speed initial download numbers have already slowed significantly. The question now becomes how fast we can expect the inevitable drop-off in players to be.

Data aggregated from other mobile apps isn't too encouraging on this score. The analysts at Appsee estimate that the average mobile game only keeps 22 percent of its users a month after their first install. An analysis by Adjust is even more pessimistic, suggesting the average game falls "to between 5 percent and 15 percent of retained users on day 30 after install."

That means, of the 100 million people that downloaded Pokémon Go by early August, we should expect that, on average, only 22 million at most would still be playing the game by the end of August. Even accounting for an unknown number of new app downloads during August, that makes Pokémon Go's current mark of about 33 million daily players seem well in line with expectations. If anything, the game might be a little stickier than average.

There's one problem with that kind of analysis, though: the average drop-off for a mobile game is not distributed evenly across the app marketplace. An analysis by startup-watcher Andrew Chen, using data from mobile intelligence startup Quettra, suggests that a top 10 Android app (which describes Pokémon Go by any stretch of the imagination) can expect to keep about 60 percent of its users 30 days after the initial installation.

By that measure, at some point in August we should have seen at least 60 million people (of the game's 100 million downloads) showing up as daily active users. Instead, by Apptopia's estimate, the game peaked around 45 million players. Different methodologies from the different companies measurements could explain some of this difference, but they only go so far. Looked at this way, Pokémon Go seems a bit less sticky than other "top 10" apps.

High peak, long tail

There is some good news in Chen's analysis for Pokémon Go's long-term prospects, though. After a significant drop-off in the first week or so after installation, Chen finds that app usage drops much more slowly over the next two months. After losing about 25 percent of initial users in the first week after install, for example, an average "top 10" app can only expect to lose an additional 25 percent of that initial user base over the next three months.

As Chen puts it, "the majority of users retained for seven days stick around much longer." Fellow analyst Ankit Jain put it a different way, "The key to success is to get the users hooked during that critical first three- to seven-day period." It's hard to gauge just how many Pokémon Go players got "hooked" during that crucial first week. Still, anecdotal evidence of the craze surrounding the game's launch last month suggests Pokémon Go might be "grabbier" than average right out of the gate. That would suggest a healthier, longer tail of continued player support.

Regardless, the numbers suggest that the current drop-off rate for Pokémon Go—i.e., losing 12 million daily users in a month—probably won't continue as quickly in the near future. Instead, we're more likely to see a slow attrition, with perhaps 5 million to 10 million more current players leaving the game by mid-October (a number that doesn't account for the new installations that are no doubt still happening).

Aggregate data on user retention after the first few months is harder to come by, but we can grab a few data points from other ultra-popular mobile games. For example, in late 2013, about a year after its iOS launch, King said Candy Crush Saga had retained 93 million daily users on 500 million total installs. And in October 2011, nearly two years after its iOS launch, Rovio's Angry Birds still had 30 million daily players out of 400 million total downloads.

Let's conservatively estimate that, after its surging to 100 million downloads in a month, Pokémon Go slows considerably, only attracting 40 million more downloads over the next year and 10 million more in the year after that. Going by the rough player-retention numbers of other ultra-popular games, we could then expect about 26 million Pokémon Go players still hunting for AR monsters daily in mid-2017 and 11.25 million daily players in mid-2018.

You can quibble with these rough estimates substantially in either direction, of course. Maybe you think practically everyone who wants Pokémon Go has already downloaded it, and new downloads will absolutely crater. Maybe you think Pokémon Go's shallow gameplay makes it more like Draw Something, a mobile hit that saw its player numbers quickly tumble off a cliff after an initial surge. Maybe you think future app updates and new features will lead to a resurgence in interest from lapsed or hesitant players.

Specifics aside, though, it's hard to see a world in which Pokémon Go doesn't continue to have millions of engaged, daily players—or even tens of millions—for a good long while. That would still rank as an incredibly successful and profitable game by any measure, even if it looks weak compared to its early peak (and even if it doesn't maintain the slower, more sustainable long term of past mobile hits).

Pokémon Go's ridiculously strong opening means it can already be declining in popularity and still be an insanely popular game going forward. And so far, there's not too much evidence that Pokémon Go's decline is out of the ordinary for mobile apps in general.

In other words, even if a gaming phenomenon as big as Pokémon Go must eventually fade away, it definitely won't do so overnight.