Except that they won't.
You have to remember, we are the exception here. Most of America's WP users don't know a Windows Insider program exists, and if they did - they're not going to run it because of that big statement of 'your warranty will be voided.' And with ATT and Tmobile doing their 'lease' programs, you have to turn the phone back into the store. It only takes a moment to see that you're not running the stock OS. Will they do anything ? I don't know, but I do know that a lot of consumers, they're not going to take the chance on it.
So for the majority of Windows users, that App gap will exist until Late 2015 if they're lucky.
And a LOT of ATT WP users bought their Nokia Lumia 920s in December/January timeframe. I know, I was one of them. The thing was $49 with a free wireless qi charger. Who wouldn't? So...what do they upgrade to? A 1520 ? Those aren't even carried in a lot of ATT stores any longer. The 830? Not really an upgrade. The M8? Maybe, but then again, it's not a Nokia, and the camera is suspect.
So they hold out...for how long? My 920 is 2 years old, and the battery is now down to giving me about 10 hours of charge a day. Nothing against the phone, but batteries have limited lifespans. They're consumables. And again, I can't be alone in this.
So where do we go? What does WP have that the others dont at this point, being they've already ported off Microsoft Office to Android and IOS, and they've already said Cortana will likely go the same route as well.
A big app gap, a tied down platform that stifles developers creativity, almost no exclusive features left, and no upgrade path.
That's not a recipe for success.