That's part of where the thinking about Tizen being all but a never-ran comes into play.
Tizen currently makes some small sense on something like a Smart TV (which could use Android, but could go with something else since you can live with "less apps") or a GPS system where it, too, doesn't "need" apps to make it worthwhile as an OS, UI, and target application.
But then, you could go with Android. The developer space is already there and the network effect for it is compelling.
In order to counter that network effect and have a chance, you'll need apps. LOTS of apps. Maybe not as many as Android or IOS have for them- but quite a few. Perhaps as many as half of what is in the Play market to start with.
I, personally, don't see that happening. Not with some HTML5 driven frameworks like Sailfish, FirefoxOS, or Tizen. You'll have to make it compelling enough to make a tectonic shift in the developer marketplace. Almost immediately. It's doable. Just not with this stuff we're talking about.