I don't think you're right. As someone who flies LH over the pond I love Jetblue. When I fly domestically in the US I try to get onto B6 or Horizon. I'd love to get Jetblue connections onto the same ticket. Note that we're not talking about transcons here, I love to take LH or another sane longhaul airline as close to the point I want to get and then a _short_ connection to exactly where I want to go. The B6 product is perfectly fine for that, and for sure a lot better than United RJs or E- in the quite likely case that they've already filled up F with upgraders, especially if you're on a discounted business fare.