You are thinking of the problem in a sciencey, evidence based way. In particular for illiterate, uneducated people there is often a huge weight given to superst

You are thinking of the problem in a sciencey, evidence based way. In particular for illiterate, uneducated people there is often a huge weight given to superstition and traditional/existing ways of doing things even in the face of evidence. It is a surprisingly hard nut to crack, sometimes even among literate educated people. If it weren't a lot of religious extremism and bigotry would not exist.