Actually... I've seen briskets go from 160F to 200F in just a couple hours... If the wrap is tight, the grill temp is above 270F or so... once the temperature inside the wrap gets to boiling point, that meat will start rising in temperature very rapidly... When I've seen this , I also experienced that the meat doesn't really get as tender as it would if it took longer. This is one of the reasons I rarely wrap meat that I'm cooking. I really think that meat/collagen needs TIME and heat to get tender, not just heat. I also don't believe that wrapping meat actually helps it retain any moisture... yeah, the moisture might stay inside the foil , but I don't think it stays inside the meat itself. Anyway, this really is at the heart of why I personally don't like wrapping meat.
Yeah, in theory there are ways to wrap that do make a good final product... but I also can make a good final product without wrapping , in fact I think I get better product due to better bark, but I'm a bark lover.