Current mobile ecosystems definitely have become heavily reliant on 3rd party apps. That doesn't mean it's the only way a mobile OS (or any OS) can succeed, nor does it imply that you need to hit a critical mass of app developers for it to be successful.
I think the Ubuntu phone will run regular Ubuntu apps and the Firefox OS treats web apps as first class citizens. Those two are leveraging pre-existing applications.
Aside from that, the only apps I use on my phone are the browser, google maps, and google voice. Who's to say the massive 3rd party application pool is even needed for an OS to really be successful? What if Sailfish just had very few really well-written and privacy-respecting apps that they sold for like $20?
I think the Ubuntu phone will run regular Ubuntu apps and the Firefox OS treats web apps as first class citizens. Those two are leveraging pre-existing applications.
Aside from that, the only apps I use on my phone are the browser, google maps, and google voice. Who's to say the massive 3rd party application pool is even needed for an OS to really be successful? What if Sailfish just had very few really well-written and privacy-respecting apps that they sold for like $20?