You need to realize that the "simple answer" isn't so simple- no one has been able to use the axioms for many worlds to make an actual calculation of anything. By kicking away the Born amplitudes, they've kicked away the entire predictive structure of the theory. You are advocating that physicists give up the ability to make predictions!

Its even worse when you go to quantum field theories and try to make many worlds work- the bulk of the amplitude will be centered on "world's" with undefined particle number.