Because that is one of the benefits of a JV. You don’t have to do the flying to get the revenue/profit. The airlines coordinate what aircraft/airline etc would maximize the profits while maintaining the negotiated restrictions in the JV as to percentages of flying done by each airline.

And I’m not sure you want to use Delta as a model for JV’s that benefit a pilot group. Well unless it’s to benefit every other airlines pilots but DALPA.