Well... original EPCOT was IP driven... by the corporate sponsors. Without them, would any of those big edutainment rides have been built?
Then there was the issue of upkeep. Showcases of modern technology grow stale and outdated. The World Fairs which EPCOT was emulating takes care of that by breaking down and re-opening every five to ten years later with new sponsors and brand new attractions featuring the brand new technological edge. Did anyone planning EPCOT also plan to scrap the attractions and build new ones in their places every 10 years like World Fairs do? Did they really think those pavilions were good to go for the next 50 years?
Or did anyone think that a sponsor would want to pay the sponsorship cost for 10, 20, 50 years? Or that the sponsor would have the cash to do so? Or even continue to exist (sorry, Kodak). Or pony up for expensive refurbs and updates?
Are their sponsors beating down the doors of Disney looking to pay a hundred million dollars for an edutainment attraction so they can put their name on it? Is Apple looking to create and sponsor a Personal Tech Pavilion (one that they'd have to update every 18 months)? Is Amazon looking to create and sponsor an Economics of Trade Pavilion?
And if sponsors aren't sponsoring them... then Disney has to sponsor the attractions. And if Disney's doing the sponsoring... well, they have a product to advertise... their established IPs.