I don't know the stats, but I'm fairly convinced anecdotally there's still a huge segment of users who don't know or care about apps, and don't much know or care about the OS either. They'll use whatever ships with the phone.
If you're an OEM, how would you target these people? As long as you can get a clean, attractive, easy-to-use OS, you'll take an interest in one that's easy for you to customise, and ship with solid default apps, some of which you can monetise on. I think Firefox OS offers that possibility to OEMs, they get to completely control the experience and keep the relationships with customers. And the customisation process - being HTML5 - is arguably simpler and less of a specialised skill.
If you're an OEM, how would you target these people? As long as you can get a clean, attractive, easy-to-use OS, you'll take an interest in one that's easy for you to customise, and ship with solid default apps, some of which you can monetise on. I think Firefox OS offers that possibility to OEMs, they get to completely control the experience and keep the relationships with customers. And the customisation process - being HTML5 - is arguably simpler and less of a specialised skill.