In my opinion the pro (the 9000, not the author of this topic ) is still the Yamaha flagship; the Tyros, in Yamaha's own words, is a keyboard aimed at the home market and not at the professional, gigging musician. I hope that nobody will take offense for what I am about to say, but when I played the Tyros I had a definite feeling that it was a budget keyboard, and by no means a flagship; yes, it's "cute", but it looks and feels like a budget keyboard, more or less like the PSR 2000 (too bad that the price is NOT budget...)
Of course right now Yamaha is all concentrated on the Tyros, but my guess is that as soon as the Tyros frenzy is over, they will continue to support the pro (and of course also the PSR 9000).
Like Graham wrote, a keyboard like the pro today would have a prohibitive cost and so I have a feeling that in the future it will keep a good value on the used market.