I think those two theories might be considered as two factors promoting altruism and their should be tested in (unrealistic) simulations to find out how powerful they are in causing altruism.

Realistic, natural scenarios are not good for spotting significance of multiple factors. As with the bike, natural realistic bike just does not fall, and why is that is left for discussion, but when somebody builds a bike that nullifies some probable cause then it can be plainly seen that other factors also might have significant role.