I don't see why using a 3rd party player is a problem. It's only a couple of taps in the app store and one tap to set it as the default media player.
That said, I hink Jolla has better chance than Nokia had with MeeGo. Jolla operates in a startup culture where the sense of urgency is clear. Nokia operated in a complacent incumbent culture.
For an example of this culture remember Anssi Vanjoki comment in 2007 how there is a "5-step plan" to make maemo consumer friendly. "Yes Iphone has launched, lets not hurry, instead lets use 4 years and two steps till we launch N9..."