People aren't interested in apps. They're interested in capabilities.
The apps markets are good for ... delivering a completely dizzying (that is: intentionally discombobulating and confusing) array of crappy software that sometimes works, always intrudes on your privacy and steals your personal information, and frequently goes titsup.com for no particular reason and with limited notice.
I don't want apps.
I want decent browsing capabilities with document management.
I want explicit control over networking.
I want a messaging capability. SMS, IRC, eMail, whatever -- there's no reason these need to be split out.
I want a multimedia player.
A basic set of utilities. The same ones as were on the Xerox Alto 48 years ago: A calendar, calculator, notepad type editor. Basic spreadsheet wouldn't hurt.
These days something with maps and an encyclopedia would be handy. Stills/video camera and gallery.
And since I'm not the 99.98%, I'd like a goddamned full-fledged shell running Linux or BSD.
But StuffMyCrapWebsiteIntoThisApp.com? Not so much.
I think it's pretty simple: people want to use apps on their phones, and no phone OS is viable without a competitive library of apps.
Most major apps are developed for both iOS and Android, and convincing app developers to develop for a third platform is going to be a tough sell, unless that platform is very attractive to users. However, to be attractive to users, it will have to have a lot of apps already...
I suspect that the only way to gain marketshare for a new mobile OS is to ship it with an Android or iOS compatibility layer, which would be pretty difficult to do well. The developers would have to re-implement the entire iOS or Android API, and keep up with all of the changes. If they did that, there would be no incentive for developers to target the native APIs of the OS, because they could just target Android or iOS like they do already. So, the compatibility layer could never be deprecated.
So yeah, I think we're stuck.