Who knows? It is all still speculation.
On the positive side I can say that he does have the reputation of being a big sports fan. He does seem to have the right intentions with the Dolphins nobody is questioning his motives there.
Much like the Dolphins, Everton have great history and tradition, but are a team that haven't won trophies in recent times, as a club they have great potential. Perhaps that kind of thing appeals to him?
He is spending money on their stadium too.
Anyone who has that kind of money is probably going to have some kind of motivation behind any purchase.
Man City for example were bought out to heighten the profile of Abu Dhabi and the brands associated. If a world leading sports team is associated with your organisation then, if marketed well, the associated brands are boosted. It opens further avenues of revenue stream as well as boosting brand awareness in countries that are difficult for your businesses to break into because of the existing dominance of other companies.
Other owners are difficult to guage, the Glazers could afford to leverage United against the value of the club because it was already a money making market leading brand. United will eventually pay off enough of their debts simply through the profitability of the club, the fans might not like it but it will work for them.
Venkys who knows? Probably wanted to tap football in the Indian market but their leadership seems to have been attrocious.
FSG and Kroenke are different again, they're sports moguls who want to own multiple, successful sports brands, the financial motivation of it is less clear to me. Perhaps you buy a team, grow the brand, increase the revenue, make more money.
At a guess I'd probably put Ross in the same category as FSG and Kroenke.