Well, in principle physicists would be more than happy to explore radically different theories. But the thing is, physicists tend to worry if a effect is observ

Well, in principle physicists would be more than happy to explore radically different theories. But the thing is, physicists tend to worry if a effect is observable. So a alternative theory needs to be compatible with all experiments that have been done until today, and second it needs to predict an effect that is observable within current experimental ability. (Or an effect that is close.) There is today just not something radically different aviable, which passes these two tests.