If that net worth is true, he acquired that mostly by being born. Compared to Walt or his Father Roy, he was nothing. He didn't know how to run the company and managed to get Ron Miller, his cousin in law by virtue of the fact that Ron was married to Walt's Daughter, taken out of the head position. He might have been instrumental along with the actual brains behind the Save Disney movement, his friend Stanley Gold, when the Company was in real danger of being taken over by hostile means and the company sold off and ultimately becoming pieces parts. I suspect his name endorsing the change helped but on his own I think we would all be buying pieces of Small World on eBay. Anyway that in conjunction with Michael Eisner managed to keep the company by making Eisner the head cheese (as it were). Roy and Friends were also responsible for getting rid of Eisner and replacing him with Bob Iger.
Many had high hopes that Iger would concentrate on the parks, but Iger focused on the company as a whole and invested in many things that were diversified and got The Disney Company to a very secure financial point that enabled it to continue on through a number of economic downturns. Roy by himself, really wanted to be as good as his Uncle Walt and his Dad, but fell very short of that ability.
Personally, I think that through the years Roy Jr. was treated very badly even by his Uncle Walt, but he just didn't have whatever was necessary to be an effective leader.