There's an element of truth to the storyline they are playing out now. There likely WAS a deal of sorts in place - Shane would go and "prove himself" outside of WWE as a business man, as it's clear that when Vince DOES go, Linda does too thus, they need someone with experience outside "the wrestling bubble" as the danger would be Trips and Steph don't have that wider knowledge. I've long suspected we'll see Shane take Vince's role as Chairman, Steph taking Linda's role and Trips remaining COO in charge of Talent and "the show" itself.
That makes a lot of sense, frankly.
(I was also never sure how much Stephanie and Shane's shares were real or kayfabe anyway. Did Vince really hand Stephanie 25% of the family's stock when she was one year out of college? I guess so, since that's the same timeframe as the WWF IPO.)