One decent promo (although the one of the best today) v. a rambling nonsensical cartoon character that can't get himself over even when he's playing the villain to some of the greatest babyfaces and superstars in the last few decades? No thanks.
Add to this that Wyatt is still terrible in the ring, I can't imagine him taking 16 suplexes from Brock correctly. This is not a feud that could ever be good, no matter how hard Brock or Paul Heyman carried it.
Can't get himself over? Based on what?
His merch sales - do you have those numbers?
His Main Event status - WWE are notorious for pushing whoever they want, whenever they want. If it was based on crowd reaction, Daniel Bryan would have been the top focus a year earlier, and at one point, Zack Ryder and Santino would have guys with a lot more time.
Whenever his entrance hits, the entire arena, pull out their phones and participate.
Wyatt is unique that he's an Upper Midcard guy, who can take a loss every day of the week but because of his unique character and promo skills, he stabilises himself. Its not Wyatt's fault that after the Cena feud, he became cannon fodder. WWE are just not ready to give him a solid story run.