I do think the pricing models are changing to accommodate the idea of giving away the negs though.
Getting paid properly upfront for shooting is one way to take after-the-fact print profits out of the calculation.
Timing is another, delivering the negs after say, a year. If I haven't made the print sales in a few months I'm probably done chasing that client, deliver the negs on "their" first anniversary and ask for referrals instead.
A third option is being a great printer. If your printing can stand on it's own as a salable product you become very hard to replace regardless of who has the negative.