If you are able to recognize that diversity of opinion is desirable, why can't the person in charge recognize this, and create groups that work on different ideas in tandem?

Once the ones that are successful bear fruit, those that are working on the failures can be moved over to the successful groups. And instead of the current environment, where there is a lot of wasted effort allowing an inferior product to go all the way to market to languish there, the decision can be made much earlier than that, saving all those wasted resources.