Emphasis on could. What we have now is necessary but not sufficient for that to happen.
It's going to be really interesting to see how it plays out. Even assuming it does get adoption, the most likely path is device makers and carriers taking the open source version and customizing the crap out of it and releasing their own "closed" versions of it, just like Android. And if HP does anything to prevent that then what we inevitably have is something less open than Android.
I do very much like the fact that Google now has another player that will keep them honest about how "open" they are.