The air burst is caused by air pressure (well, plasma pressure) compromising the structural integrity of the meteor, not by overall heating of the meteor. To quote from the Wikipedia link:
In essence, the meteoroid is ripped apart by its own speed. This occurs when fine tendrils of superheated air force their way into cracks and faults in the leading face’s surface. Once this high pressure plasma gains entry to the meteoroid’s interior it exerts tremendous force on the body’s internal structure. This occurs because the superheated air now exerts its pressure over a much larger surface area, as when the wind suddenly fills a sail. This sudden rise in the force exerted on the meteoroid overwhelms the body’s structural integrity and it begins to break up. The breakup of the meteoroid yields an even larger total surface area for the superheated air to act upon and a cycle of amplification rapidly occurs. This is the explosion, and it causes the meteoroid to disintegrate with hypersonic velocity, a speed comparable to that of explosive detonation.[8]
What would be doing the ablating above 90 km? Even at that low elevation q is still only equivalent to a stiff breeze. It’s spending, what, a minute maybe, at any appreciably high temperature and q. That doesn’t seem to be enough time to heat a significant amount of a steel ball that size. Is there even enough energy in a column of air as wide as the sphere and 400 km tall to heat up the entire sphere to its melting temperature?
I saw Munroe speak last year, and he mentioned that after he published the “Steak Drop” column he was contacted by a couple of university researchers with access to a wind tunnel who had put this to the test. And the answer was pretty much exactly this:
The outer layer “cooked” and ablated way too quickly for any heat to transfer to the inside, so it was just a matter to losing layer after layer as time went on.
He also said that the researchers then had to spend the whole night cleaning tiny bits of steak out of the wind tunnel.
Some experiments are much easier as thought experiments.
Although I gotta say, putting steaks in a hypersonic windtunnel (especially a taxpayer-owned hypersonic windtunnel) sounds like one the greatest examples ever of “The difference between men and boys is the price of their toys.”
Overall, their results matched my answer in the chapter pretty well! The the surface of the steak was cooked by the winds, charred, and blasted away, while the interior stayed cold and raw. Conclusion: This is not a great way to cook steak.
