I would suggest that a contributing factor is that the apps referred to are time-sink / gimmick applications.
Certainly in the arena of gimmickry, such things are surely designed to be a diminishing return from initial surge, much like the "1-hit wonder" in the music charts. At first it is novel but after 2 weeks we begin to see it's dwindling shelf-life. No, really... everyone wants to see Mr Blobby release another Christmas single this year.... don't they?
Another factor would be the sheer number of apps developers all trying to do that very same thing, all at the same time; niche application is now app saturation. If there isn't already an app for scratching your back-side, there probably will be soon*.
Looking at the most recent comments for the Android version of "QuizUp" (as mentioned in the original article) it seems to be evident that it's quality is sliding. Possible reasons:
- It was a short-term horse.
- Up-take (and subsequent number of "testers") have highlighted too many issues for the current dev team to be able to adequately cope with.
- People are growing weary of mobile-based micro-transactions in applications they know are not going to hold their attention for very long, therefore reducing the profitability of the app.
"Are we becoming app sluts?" - Hunter Walk
To this I would say that ultimately it would depend on why someone installs a new app. Are you looking for something that improves upon the functionality of an app you already have (an app that perhaps has stagnated)? If so then it is just the pursuit of a better life. If, on the other hand, you are a serial-installer.... well.. maybe? :)
Games on mobile are subject to the same "rules" as PC / console games:
- Ease of access
- Re-play value
- Competitive peer-interaction
If you manage to draw upon any one of those then there might be something in it which would contribute to a waves of usage; re-play value means each cycle has the potential for attracting new users, immersion will generate kudos, ease of access will mean more people will be inclined to play it and peer-interaction will always keep you coming back, to try and beat Gerald in Accounting.
Chat has to be the most volatile group; at the very least, each generation will require a new chat app as no child wants to be using the same service as their parents (consider, my-space, facebook, friends re-united). The best hopes of "chat apps" now is convergence of services, into a central UI with a bespoke twist that answers a need.
Photo editing (of the nature mentioned by Hunter) will always be the remit of gimmickry. Each app will be it's own one-hit wonder, assuming it does something different from the others.
"You won't have time to faff if you're always having to doProductivity apps, in my opinion have to be the area that hold most promise of long-term return. As with any software that is designed to make a process better, if it it does what it promises well, it will become part of the Users routine. Once you're in, as long as you don't do something stupid (like shut-down when the inevitable bugs start rolling in), you're gonna be pretty much "safe".
shitstuff" - Me
So, the answer to "why does no-one use your app any more?" is probably because it didn't have long-term value.
* Author accepts no responsibility for someone reading this and actually writing such an app.