There will still be flashable versions for the N900 I'm sure for quite some time all. So as MeeGo becomes "mature" you'll still be able to flash it and use it.

Now.. whether there's actually going to be a "user" experience that degrades between the use of capacitive or resistive *shrug*.. but it'll be there for those who want it I'm sure. (They'll just say it's "devel").

(ETA: I am, however, saddened they decided not to official support it.)