the question is, are you happy with the Z....my answer is yes, what happens to the next generation is meaningless since I like what I have. I could have bought a Camaro, a Mustang, a BRZ, a GTR and the Z was what I wanted, now I'm a happy guy who smiles at it when I walk away from it and when I turn it on in the am.
If they discontinue, well the Celica is gone and I drove mine until it had 300 K and was in a glory even when it went from RWD to FWD...enjoy what you bought and stop looking into what the Z will look like or if it will go away, my 2 cents