Why did Disney never plan to have Pirates of the Caribbean in Walt Disney World?

Guests at Walt Disney World take Pirates of the Caribbean for granted as something that's been there ever since the park opened in 1971. The reality is that if one Imagineeer had his way, not only would there never have been a Pirates ride in Florida, but in its place a massive attraction putting it to shame. So how did Pirates of the Caribbean come to be in Disney World?

When the Magic Kingdom at what would become Walt Disney World took shape, Disney Imagineers planned for it to be a near copy of Disneyland. The one major change was that rather than New Orleans Square, there would be Liberty Square, paying homage to America's history and home to the Haunted Mansion and the Hall of Presidents.

This meant no place for Pirates of the Caribbean. But as it happened, that was never in the initial WDW plans. Disney executives believed that Florida already had plenty of attractions based on real-life pirate adventures, so guests there wouldn't be interested in a batch of robot ones. 

Instead, Imagineer Marc Davis had conceived Western River Expedition, a fantastic new water ride that would take guests through a Western town with waterfalls and Audio-Animatronics of cowboys, Indians and more. It would be housed in a huge "mesa" dominating Frontierland and be the hottest attraction in the park. 

Due to cost and construction issues, the ride wasn't ready for Opening Day, but the plan was to have it up by 1974. But then a reaction hit that Disney really should have been ready for.