To succumb to something means to give in or yield to it, while to rot away means to decay or decompose.
Context: Find a 1980 Toyota Corolla or 1982 Nissan Sunny that has rotted aways , and you will lose money .
Hypothesis: Find a 1980 Toyota Corolla or 1982 Nissan Sunny that has not succumbed to rust , and you can buy with confidence .

Given this context, is the hypothesis true (Yes/No/I don't know)?