TRUE, but I think it just became even MORE obvious at EPCOT because those experiences HAD to be updated or they were out of date - information and content wise. Other parks may have had attractions that were threadbare or in need of refreshing, but they were designed to be "timeless" so it wasn't as obvious as with attractions designed to be TIMELY.This mindset really has little to do with EPCOT. Disney was doing this with sponsorships across the board. By the 70s Disney was no longer the guy begging to borrow money but was in the position to charge for access to itself. Be it Disneyland, MK, or the new EPCOT - this was common place.
Disney riding attractions out long after they are stale while they hunt for a new sponsor was not an EPCOT problem at all - it was a Disney problem. Addicted to free money.