Rami Ismail of Vlambeer points out some of the problems with the mobile app ecosystem: platform SDKs update so often, so older mobile games often break, such that the reasonable option is to make freemium games that you update continuously rather than single purchase games that won't work a year later unless you burn capital on them:
"... I’m just a little wary of the smartphone market right now. I don’t currently feel at ease developing for those platforms because the SDKs change, their hardware specs change and when you don’t update the game just breaks."
I noticed this a while back when I was looking at what games I had previously purchase for my iPad on Apple's App Store and found that many of the older purchases are either no longer available for download or simply don't work anymore. (I imagine that Android has a similar issue, but I've never purchased anything from the Play Store, so I won't bother to check.) For this reason, I have resolved never again to pay for any games on mobile. (Actually the last purchase was as far back as 2013).
Unlike consoles where the platform SDK is locked in for an entire generation, mobile app SDKs are updated on a regular basis, which means mobile game devs need to support the equivalent of new console platforms more than once a year. Mobile gaming fares even worse than PC gaming, despite the wide variety of PC configurations, the software-level support for games is pretty much standardized at the OS-level and companies like Microsoft are careful to support backward compatibility.
One of my pipe dreams is of course to get into game development, and for a while I considered mobile as a possible option for that (if I ever get around to it), but with the state of the ecosystem these days that seems unlikely.