Since the beginning, Kripke has compared Revolution to Lord of the Rings. Sword fighting, medieval economy/government, lack of modern conveniences, crossbows -- you can kind of see it if you squint just right.
Now, we have a quest for a Tower and the nanites becoming indistinguishable from magic (in the last few episodes, we've seen the nanites heal people -- or rather, keep them alive -- and set people on fire).
I predict that the show will NEVER turn the lights back on (the entire "high concept" of Revolution is what happens after the lights permanently go out) and we'll see the world become more "high fantasy." More nanite magic, less bullets. More Game of Thrones, less Jericho.
That's my guess, anyway.
I vibe with what you're saying...I am guessing that the Tower will be blown up...but what that does is take away any immediate hope of the power returning...but then we find out that other scientists are out there, who can reconstruct the tower...and that will be the finale of the show. In the meantime, each season might be a quest to find certain scientists, living across the country