1) It's great that the ideas that Rails popularized are being adopted on other platforms. But besides for Django which has a) been out for almost as long as Rails and b) uses a great dynamic language, the other camps you mention doesn't have anything resembling the "Ruby on" part.
Just grabbing the grabbing the general ideas of Rails are trying to fit them into less expressive languages yields some less than desirable results. Have you actually looked and compared any of the code back and forth?
2) Hahaha. The web has been pronounced dead on more occasions that I can count, but RIA has been the boogeyman since the beginning of the last decade. Don't invest your piggybank in it happening this time.
Additionally, I know of lots of Rails apps that are using all those technologies for the front end. Whether your output is HTML or Flash or whatever, you're going to need a backend to handle it. All the benefits of Ruby, Active Record, Action Mailer, and the works are as relevant as ever with that.
3. What does this even mean?!
Anyway, good luck betting.