It's not the advancement of the trucks. It's the change in the landscape of the sport. Manufacturers are much tighter with what racing programs they will invest in, and the objectives are different. The landscape is radically different from what it was 30 years ago, on road as well as off. Look at how Indycar has declined, or even NASCAR. Look at the difference in how sports car racing is sponsored and supported. It's a different world.
If a manufacturer wants to win Baja, all they need to do is throw money at Bryce or Andy or Rob Mac. Yes, there is a small amount of association (articles about Luke call his truck, nominally, a Ford) but these Trophy Trucks are as close to Ford Raptors as the Mustang Cup Cars are to the things we see on the street every day.
The issue isn't the type of truck. It's the marketing landscape.
Agreed...I can't tell you how many times I heard John Force refer to his funny car as a Ford Mustang over the years. There is NO PART of that car that is a Ford Mustang part. It kinda, sort, maybe from a distance, or you close one eye looks maybe just a little like a Mustang in the front.
I believe the moniker, "Win on Sunday, sell on Monday" is pretty much dead now. And the manufacturers got themselves in such a bind with the cost of the pensions the Autoworkers Union forced them into they don't have nearly as much money left for sponsorships like they used to have.