What rlslmshdy said. The REALLY hot stuff is either a niche market or a gimmick. No big producer will ever make anything hotter than what the majority of the consumers can handle. Besides, that same majority wouldn't even know what those SHU numbers represent. They'd need a scale comparing it to Jalapeños or something.
Edit: To clarify the gimmick part, for example here in the Netherlands we have Doritos Roulette (dunno if it's worldwide available). It has a few 'extremely' hot chips in the package. Almost nobody here would buy a bag full of those hot chips. But because they're marketing it like a game where it's funny when someone eats the hot chip, it's very popular.
More hoops to jump through to be a producer for an end result that isn't even going to help anyone, given that Da Bomb's Beyond Insanity is officially about 1/19 the heat of Hot Ones' The Last Dab and still tastes stronger.