Your point about Page Rank is unfounded. Google doesn't look at pages it has already indexed to figure out Page Rank. It gathers a fresh copy then follows those links which would all work. And anyway, most of Page Rank is about other people linking to you.
If links stops working after a while, I'm pretty sure people will stop linking. And if not, visitors following the links will get a bad experience.
You may be right that it wont hurt page rank directly, though.
