I stumbled upon an online 'discussion' on my Facebook wall last week that was debating the recent decline in iPhone sales.
One poster was arguing, quite legitimately, that a drop in iPhone sales was not necessarily a problem for Apple, and that the only time it should be worried is if there was a drop in iPhone users.
As long as people are still using iPhones, buying apps on the App Store and listening to music via Apple Music, then it doesn't really matter if they bought the latest model or not (unless you're a component manufacturer or a shop).
There's a reason I'm discussing Apple in a piece on Call of Duty, because there's potentially an interesting parallel between the iPhone and the world's most popular first person shooter.
The recent Call of Duty: Infinite Warfare was commercially disappointing. Early US figures (for boxed sales) suggests the game's first month performance was around 50 per cent lower than last year's Black Ops III. In the UK, the new game is currently tracking 37 per cent behind its predecessor (that is an improvement over where it was a month ago, but we're still talking hundreds of thousands of units down).
We could spend all day postulating as to why these figures are so much lower - from the digital transition to softer market conditions. But the question that matters to Activision (and the wider games business) is: where have these lost Call of Duty players gone?
"The biggest threat to this year's Call of Duty may have been last year's Call of Duty
Battlefield 1 from EA is one possibility, and that game has certainly been a big success. Yet its sales are largely in-keeping with how well that franchise has always performed - it's certainly trending in line with last year's Battlefront and 2011's Battlefield 3. So there's no real evidence to suggest that there's been a major defection from one franchise to the other.
Titanfall 2 may have had an impact. It is made by the former Call of Duty creators and has certain similarities to that IP. However, this game has been a big disappointment commercially and its early sales suggests that far from hurting Call of Duty, the reverse has occurred.
There is a third competitor to Call of Duty this year, one that Activision - of all companies - should have foreseen. And that competitor is Call of Duty.
According to SuperData, 2015's Black Ops III was still selling over 30,000 units a month in the UK in the period building up to this year's Infinite Warfare. The firm also says that Black Ops III had a far higher level of engagement after launch than its predecessor (2014's Advanced Warfare) and was generating more money per user, too.
"The main thing is that Advanced Warfare didn't introduce microtransactions until May 2015, so six to seven months into the game's lifecycle," SuperData told GamesIndustry.biz. "Black Ops III, however, had those from December, about one month in. If you look at ARPU [average revenue per user], Black Ops III's number is much higher than Advanced Warfare almost all the time. That's because people have something to spend money on from the very beginning. Also if you look at Monthly Active User curve, Black Ops III is much higher. That's because it's part of the most beloved sub-franchise, so it attracted way more players and managed to keep them longer - partly again because of microtransactions."
Black Ops III was a big success for Activision, and with consumers engaging with games for longer (see Rainbow Six: Siege, Destiny and Star Wars Battlefront), it's entirely reasonable to suggest that some gamers didn't buy the new Call of Duty because they were still playing the last one.
In fact, considering the engagement figures surrounding Black Ops III, it seems short-sighted of Activision that it stopped developing new maps after just half a year. The model around video games has changed, and most developers are releasing DLC and launching special events for its titles for years after release, not just months. This isn't a concept that's alien to Activision Blizzard, in fact the firm helped pioneer and popularise the idea through the likes of World of Warcraft and Destiny.
That's not to suggest Call of Duty should move out of its current annual cycle like Assassin's Creed has - at least not yet. For all the negative headlines around Infinite Warfare, the game has still been a major seller. In the UK, it's fast approaching 1m sales - that's much slower than last year, but it is still ahead of Battlefield 1 and only bettered by FIFA 17. That figure alone proves that it still has a sizeable addressable audience that is willing to buy the game every 12 months.
Yet it does suggest that Activision and its three developers - Infinity Ward, Treyarch and Sledgehammer - should take a more pragmatic approach to the type of Call of Duty it makes each time.
The last three Call of Duty games - Advanced Warfare, Black Ops III and Infinite Warfare - were all set in the near(ish) future, with advanced weaponry and sci-fi mech suits. Is there a need to buy this sort of experience every year? Call of Duty's brand identity is broad, taking in multiple eras over its 13-year history, which means there's no need for the repetition that the brand is currently suffering from.
EA has been doing a far more effective job with its variation. If you take away Titanfall for a second (which is actually owned and developed externally), EA's last four major shooter games have been Battlefield 4 (set in the future), Battlefield Hardline (a crime-based cops vs robbers-style experience), Star Wars Battlefront (licensed sci-fi) and Battlefield 1 (historical... sort of). All four titles are capable of living side-by-side, because although they ultimately appeal to the same audience, they do offer alternative experiences that means it's far more reasonable for these gamers to invest in more than one.
Call of Duty is still a powerful gaming brand, and its overdue Hollywood adaptation could see it become even more widespread. Yet despite its futuristic settings, the series' business strategy is starting to look decidedly out-of-date.