It can’t. At least not given the current policy on publishing exit lists. That was my point. The technical part is already solved.
Yes. Even if we did away with the exit lists, and every exit had a separate exit address which was hidden from the consensus, many exits very well may still be discovered and blocked by other means. We just don’t know for sure because we haven’t tried it (and can’t, because Tor Project doesn’t allow it).
Using hidden services to replace exit nodes (aka. “exit bridges”) could potentially allow us to test the concept of unlisted exit addresses and see if it makes Tor more usable in the real world.