We have real life examples of 100+ year old PT prints. We have real life examples of 90+ year old fiber prints. We have real life examples of 30 year old RC prints.
I use RC paper, but I don't believe it is as good as fibre. I like that it dries fast and flat.
After having seen Jorge's PT prints, Alex H's and M. Smith's azo prints and comparing my own RC to fibre prints, I reach the conclusion that for me fibre looks better.
If Stieglitz's prints had been on 100 year paper, they would be lost by now. Lost forever. While the negatives or plates could be reprinted, we could not know they were the same. While 100 years may seem like a long time, it's not as long as 1000. Maybe its long enough, maybe not. Regardless, my good prints will go on fibre.