Wow... Natasha's Colorado is almost at 50K miles. Goofy hat here I come!
But, the monthly payment is pretty significant between the F150 and SDs.
I'd guess there's some low interest financing incentive for those with an 850+ credit score at work there... maybe some different cash rebates, who knows. Also the weird online thing added random equiptment.
The normal person gets the same finance rate through their local bank regardless of brand or trim they buy so that's also fairly meaningless. Very very few buyers qualify for those highest tier rates. Trade ins, loyalty, conquer incentives, region, all that could throw that even further out. One way or another. You could go even further and get costCo discounts that may differ trim or model to another.
Point is, list price, msrp, at the same trim level, no longer a real price differential between a 1/2 ton and better truck.