I think you can forget the latter. More likely the non-TB model will disappear completely would be my guess.
Whether the TB will disappear in the next redesign is a more interesting question to speculate on, but it's impossible to guess. If it starts to appear on other models we'll know that they are doubling down on it. Otherwise the only reason to keep it would be because Apple never admit to making mistakes, but that might be enough.
Yeah, I certainly don't expect it, but one can dream.
Good point about the other models: will be interesting to see what they do with them. It does seem like some revision of the concept is more likely than ditching it - hard to imagine them going back to function keys. OTOH, Apple never admitting to a mistake doesn't necessarily preclude getting rid of it - if they do it'll just disappear in a future design revision and they'll just never mention it.