What if the OS could dedupe pages?
Also, it's quite likely that static linked libraries wouldn't be located at the exact same page offsets every time they're linked in to a binary, making page-level dedupe not useful.
Linux does have something called "KSM" that de-dupes memory pages, but it appears that it's only so a hypervisor can de-dupe guest OS pages? Odd that it's not more general than that. Though I guess there is a cost: the KSM code needs to scan through memory to find duplicate pages, which I can't imagine is fast.