They're exactly where they would have hoped to be in life at their respective ages, bearing in mind their father is still alive and active. Neither was ever "getting the company" once they went public, as the shareholders will always have a say and Vince isn't gving up control until he is dead...
Shane admitted that he was frustrated and went off on his own, but also had a need to prove himself - which he did. he took the money he had from his first WWE run/cashing out and made it more... then came back on his terms. He is only talent right now, but it's crazy to assume that Trips and Steph wouldn't want him just as involved as they are once Vince goes... for one thing, Shane has the fans... he is the one McMahon who is universally respected... the boys like him cos he does what they do and puts on great matches, he cares about the product. He is respected within the WWE itself for pioneering a lot of what they do today online when he had the website and Byte This etc... The fans like him because he is not outwardly in it for power or gain, he came back cos he loves it...he wrestles cos he loves it and the fans love him for that.
Shane is respected outside the WWE because he built a business in difficult circumstances, getting into China wasn't easy, much less being a success there enough to come home "better off".
To Wall Street he is a lesser version of Vince and the guy they would want "at the helm" once he goes, both Hunter and Steph have the problem of being too closely linked with heel characters and being "bad bosses". Perception is everyhing and it's always VERY jarring the way Steph almost has to go out of her way to say "it's a character I play" whenever she is interviewed outside WWE.
Most importantly, I think Shane now has Vince's total respect... his contacts brought a very big opportunity to WWE with China and it's inconceivable that those people would do business with anyone else but Shane. He also came back and "stepped up" for Vince in the ring when Mania was looking a little lacklustre, is instinct that Shane could draw against Taker was proven right. Also remember Vince himself had to "go rogue" on his father somewhat, buying the company from him, not missing payments but not telling him of his true plans. Shane didn't buy the WWE, but he bought another company and now WWE is stronger for it... Vince hasn't bought many successful companies outside of wrestling, but Shane has.
As for Steph, she is EXACTLY where she wants to be, she has power, is able to be an influential businesswoman and a mom at the same time. She has what appears to be a solid marriage based on respect and over time has grown from "hot but annoying harpy" to at times pretty compelling performer.
When the time comes, it'll break down that Shane will be the President/CEO and Steph will take Linda's role. Shane probably won't run TV to the same level Vince does as that will be Hunter's domain, but the top level discussions and for Wall Street purposes, the siblings will be a team. However, I can still see Vince throwing a spanner in there somehow, perhaps naming Kevin Dunn or someone to the board to "keep his view in the mix".