Experiments in areas with huge numbers of degrees of freedom are difficult to sort out.
I mean, if we just take just the chocolate cookie experiment, and assume that we can replicate that particular experiment. We run 100 versions of that experiment and find that students will attempt the impossible for about twice as long as those who had to eat radishes.
What is the most general thing that we can conclude?
How about if we find the same result with candy vs celery? Twinkies vs nothing?
What can we possibly be sure we learned from such experiments?
The question then would be who would want to provide funds for that? It is not the financial backers who have problems with the current methods.
I don't think the butter vs margarine or the tea vs coffee debate will be settled within my lifetime ;)
The practice of science is a very human affair. That means politics and clan thinking. Science, like the press, develops a popular "narrative" about how things work. New research tends to magically confirm that narrative.
I suspect this has been going on for a very long time.
I love science. And I understand that there are a lot of demagogues that want to create these false battles between science and the ignorant. For many of those folks, they will want to circle the wagons. Don't let folks know how bad things are!
To those folks, I'd ask them to remember that the strength of science is its tentative nature and ability to adapt. Sure, people aren't so good at that, but science is. Stick to that and do your best to toss emotions out of it.