Pretty cool. I'm not sure I really agree, but it is certainly worth consideration and maybe a real food scientist will actually do some real testing to see if that's true.
I agree with landarc that a sponge is a poor test, and just because it acted as he expected (duh) doesn't really mean much.
The first hole I see in this comes in the form of foil. In a tightly foiled environment, evaporative cooling should not occur as much as when the steam is allowed to float away from the meat. Instead it is trapped inside and should, in theory, and in just as much theory as the sponge,
it should not see a stall then if the stall is primarily evaporative cooling. Instead what you should see is a rise in the meat temp to a point more towards the boiling point of water at which point it would then stall.
So, I'm not so sure I understand why this is being paraded around as some sort of proven tested fact in light of all of this. Honestly, this sort of thing, and the parading around of info is a lot of the reason I stopped with the experiments. I'm not a professional food scientist with a multi-million dollar lab and deep enough pockets to grab whatever pricey equipment would definitively prove this particular minutiae or that. It was getting a bit ridiculous really.
In my opinion, it is a factor to consider along with the others, and you can take it or leave it. I have a feeling the meat is going to still cook the same way no matter what you "believe". Your thoughts have little control over that. Only changing methods will impact that...and if this causes you to change your method, then expect a change in cooking.
Still though, I did find it interesting, and I do see some merit in it. I just don't think it is as significant as the author thinks, otherwise you could bypass the stall by tightly wrapping in foil to avoid any possible evaporative cooling. However, I think we all KNOW that the stall STILL happens even when wrapped in foil. So there goes that.