I gotta tell you, I think a brisket flat is one of the most overrated meats in the BBQ world. Even when done properly, I am only looking to have a slice or two. IMO it rates just above chicken breast, and just below just about everything else.
I'm thinking that you haven't had really good brisket. In my experience, 90% of the briskets are mediocre to bad. If this is all I had, I might agree with you. Another 8% are downright good. But when you find that 2%, it is nirvana. I really feel that some people just know how to cook them and can be consistently in that top 10%, hitting that 2% as often as not. Two weeks ago driving down here, I had some of the worst flat in my life at a new BBQ joint just north of Petersburg. Didn't stop me. The next 4 dinners were heavenly at original Q-Shack. For whatever reason, they were "on" that week. Last night, not so good, but tonight I'll be back and see what they do.