*sigh*
I’ve said here before - and it’s been corroborated - that the only “other” project being considered for that space was a generic Big Bang coaster that, upon going to Bob C, got Guardians slapped on it. Any sort of revamped Universe of Energy would have been years removed from the actual discussions that led to something being approved, because Epcot was firmly behind Animal Kingdom and Hollywood Studios for dollars.
The Internet fairly regularly talks itself into thinking that it’s missed out on things that are better than what they actually missed out on. See Galaxy’s Edge third attraction.