You wouldn’t expect a mathematician to ignore theories that undermine his whole way of figuring things out simply because life is short and doing so could possibly prove his whole life wasted. If such a person is out there, he is a shame to his profession.
It’s a judgement call whether to accept or reject new theories. Data is manipulated all the time in research. Anyway, you can’t compare research to life, a triangle doesn’t become a mathematician just like a mathematician doesn’t become a triangle.
In order to have the humility to accept truth over what you believe, you need to believe that your mind does not ultimately define what is true.