Yes all these things *could* happen, many people also said that one will never see and IT boom after the dot com bubble burst, yet the market is very boyant now. Investment might not be as high as in the late 90`s but the industry is very very boyant.
Now the same could be said for aviation... will there be a bust? Yes, most likely, however these things also have a tendency of bouncing back, maybe not in such a big way, but it will bounce back... much like the real estate boom.
Can you say that there will never ever been another realestate boom because interest rates are going up???
What people seem to forget is that oil prices affect almost everything, so if prices indeed go up then one must still calculate transportation costs, be they aviation or alternate and with newer engines giving airlines economy of scale, as per passenger mile costs are close to (if not cheaper) than most current hibrid cars.
Industries evolve... the aviation industry is no different, just some evolutions tend to be great big leaps (read: massive knee jerk reactions)