I like your idea BUT as these devices become more powerful the real amazing apps will consume ALOT more storage
Apps have absolutely grown in size from the time the App Store was released, that's a fact. It's why Apple added support for thinned app installs (where only that portion of the app that is either shared by all iOS devices or specific to the device the app is being installed on is downloaded) and delta updates (where only the changed portion of an app is downloaded when updating). But going by my own experience I don't think the size of apps is what's driving the demand for and subsequently availability of larger storage sizes.
Looking at my list of installed apps, the smallest app I use every day is 12 MB in size, while the largest is 360 MB. Roughly 50% of my installed apps are under 100 MB; roughly 75% are under 200 MB and roughly 90% are under 1 GB. The largest app on the device is 2.6 GB (a game), although now that I think about it it's been months since I've last used it. Removed. And quite fittingly, games are an app category where file sizes become larger as device capabilities increase, but also a category where people are willing to cull old stuff in order to create free space on their devices.
Where I feel the more considerable storage needs stem from, then, are photos and videos (including TV shows and movies for many, which are also likely to be deleted once watched if free space needs to be created). I currently have about 16 GB of photos and videos I've taken myself, on my phone. I don't use iCloud Photos yet, so my full photo library is only on my Mac and in my backups. If I did store all of my unoptimized photos and videos on my phone in addition to the apps, I'd blow past 64 GB - and despite being "snap happy" I don't count myself among power users when it comes to photo / video library size. I'm pretty much in the average Joe territory here.
And that's exactly why photos and videos are so meaningful when it comes to storage, even if you can debate that we're taking more and more of less and less meaningful photos these days. You don't have to be someone who needs "more powerful and amazing apps" to fill up your phone - you just need to enjoy taking photos and videos, and there's a lot of those people around. It's no doubt one of the reasons why Apple offers the "Optimise iPhone Storage" feature and is moving to support HEIV and HEFC formats in iOS 11.
I mentioned in my earlier post that my own phone usage has evolved over time and I've gone from 16 to 32 to 64 GB. The driving force behind that evolution has been - you guessed it - photos and videos. Fortunately my usage has evolved slower than the top storage tier sizes, so I've never been forced to buy the most expensive option available. If anything, I've taken steps to slow down that trend to the point where my next Mac (whenever that happens) will probably have "only" 512 or 256 GB of storage space, instead of the 1 TB my current one does (of which 700-800 GB has gone unused for the past four-ish years or so).
