EDITED:
Okay, I get why someone can game a difficulty adjustment algorithm and lie about block timestamps in order to create an attack chain which
a) has more blocks,
b) ends on or before the same timestamp as the main chain,
c) took less than the same amount of hash power to produce.
And so far we've focused on the difficulty adjustment algorithms to try to fix it. But I have a different question.
Why aren't these attack chains recognized as containing less work? Regardless of length, timestamps, or whatever, shouldn't they simply be recognized as containing less hashes and never given the chance to displace the main chain?
