When (and if) Acurite decides to "flip the switch", it will be an easy "out-of-box" experience, including the installed base.
I'm sure they have contingency plans if wunderground goes belly-up.
Again, they are far more aware of what's going on than some people here think.
So, have they already worked out the additional development? If so, why not release it?
Ah, the catch is probably in 'monetizing' it. Shades of the smarthub "Massacre at AcuRite Gulch" [to quote myself, heh]. If they try to set the hook too hard, this fish won't ever bite again.
I haven't even taken my Access out of the box yet, and have no idea of its' architecture. Maybe it is a flexible, adaptable Pi/NUC-type system, if so they shouldn't be hiding it, imo.