They can also help prove how steel weakens at half its melting point, and can bend.
In the sword vs. machine gun story they heated a machine gun barrel till it glowed red then bent it at a rather pronounced angle using a sword. Before heating it so much the steel did not bend. Not precisely the same as highrise fire and steel girders, but it does demonstrate the rather obvious point that steel doesn't need to actually melt before it loses strength.
However, given how many people apparently write in to nitpick on every experiment they do, I rather doubt their testing would settle anything. People like Truthseeker1234 would apparently only be convinced if we rebuilt the Twin Towers precisely and then rammed a couple more planes into them, then rebuilt them again and did a controlled demolition, then rebuilt them again and did both, then rebuilt them again and used the Death Star on them, then rebuilt them again and had magical pixies tear them down.
Even then they'd probably argue the planes hit wrong, the explosives were wrong, the Death Star wasn't in the right orbit, and they should have been fairies instead of those blasted pixies. Even if everything went precisely as they specified and the results didn't agree with them, they'd point out that anyone with enough money to rebuild the towers 5 times clearly was a government disinfo agent.
I don't think the issue is that the information is not out there, nor that we need to demonstrate known principles on tv. That being said, anything on mythbusters where they get to ramp it up and make things go boom is fine by me. (just in case you were wondering what happens when you put a few thousand lighters under a heatlamp in a car...)
