Your first and second paragraph somewhat contradict each other - I agree that some traditions may be undervalued by people who'd prefer to reinvent things from whole cloth (from a software engineering perspective: rewriting a complex system you don't understand is risky), but as you say, traditions may have been selected for self-relication more than for their actual value to humans.

If you consider selection at the family, village or tribe/nation level, maybe tradition's "fitness" is how much they help the people that follow them, but many traditions are either quite recent, or evolved in a pretty different environment. So I don't know how much value to attribute to tradition in general.