Nokia/MS mobile unit doesn't sell any Symbian products anymore. The last phones were shipped by Nokia last June. Manufacturing ended even before that. There might still be some units in the resellers suply chains, but Nokia/MS doesn't make any more money from those.

Personally, sure open up every last bit of Symbian. But what I would really like to see is Nokia/MS opening the closed bits from Nokia's Maemo and Harmattan/Meego stuff. Unfortunately that won't ever happen, just like it won't happen with Symbian.