My thoughts exactly.
Just the thought of interline bag transfers will add a slew of time, energy, and costs. And that's once it's up and running and doesn't include the cost of infrastructure investment to make it happen.
And international airlines could also require some more perks for their customers, as codeshare partners often do. If B6 had to add galleys and serve food, do you have any idea how much cost that would add in training, removed seats, and catering?
This would be a serious move away from the model they were founded on. Potential revenue? Yes. Potential disaster? Absolutely.