"I think that if Fischer and Karpov had actually met and played for the title right away as was scheduled, Fischer would have crushed Karpov"
Fischer scored 12.5-8.5 against Spassky, and Karpov was a greater player. Whatever the hypothetical result, I don't think anyone could have crushed Karpov in the 1970s-80s. Kasparov played five matches against him and all were quite even.
Karpov, of course, is a fantastic player. He is also one of my favorite players. However, I said this before and will say it again: it's impossible to know how things would've played out if the match with Fischer took place. I agree with Fischer's demands though that the match should've been long and the challenger should've been able to demonstrate superiority by beating the champ by at least 10-8.