Who knows what would have happened tbh.
A huge what-if is if the influential historians opposed to building the park because it 'cheapened history' were able to compromise and not push for cancelling it's construction, perhaps they would have influenced legislation that prevents Disney from bringing in IPs not related to the historical theme - you could have classic characters portraying historical figures such as Donald Duck portraying Teddy Roosevelt, etc, as well as Pocahontas being right in the sweet spot (though tbh, I don't remember there being any large cliffs on the Jamestown side of the river, only some bluffs on the Surry side, but I digress).
Another is if there was no opposition and the park was built as planned - as evidenced by California Adventure and Hong Kong, there's no really good way to build an immersive themed Disney park for the kind of budget Eisner was thinking would be spent on this park - it's doubtful that they'd have been able to build everything as planned and have them be of a 'Disney' caliber.
Then there's local competition in other parks - it's a really huge gamble to come in decades after KD and BGW were established in Virginia and after the PA parks were established (don't know then SFA came about) and expect to take significant chunks of their market share when they're all relatively less expensive at the time and are either en route for those driving to the DC area using some of the major North-South or East-West corridors that connect huge population centers (looking at a map, I-66 really serves to connect DC to I-81, but the only population centers it serves could be considered Virginia suburbs of DC (yes, I know, not everywhere in NOVA is affiliated to DC, but the highway is well-known for people commuting for work in and around the nation's capitol.)), unlike Haymarket which isn't particularly easy to get to in comparison. And those flying in would have the added hassle and expense of renting a car to leave the city either way unless Disney offered a cheap shuttle service.
So, again, who really knows?