It's less simple than you think. Chrysler essentially invented the modern minivan and had a massive jump on sales in the 90s. Great competition like the Sienna didn't happen until the late 90s. When you have a popular new category and no competition, I'd expect to kill it like Chrysler did.

BMW doesn't have any trucks, and Honda didn't for a long time either. It's easy money but it's not the only way to make an auto brand.

(Fun side note: VW's minivan was a rebadged Chrysler.)