Looks like some revisionist history in this thread.
Wish being featured in this parade reminds me of how The Black Cauldron was a big part of The Cinderella Castle Mystery Tour when it opened in 1986. That was the year Black Cauldron was due for release in Japan and I'm sure it seemed like a good idea at the time to include the upcoming movie as a tie in.
These things take many years to develop. A new night time parade has been rumored for MK for a long time now, at one point supposedly for the park's 50th anniversary.
We know there were high expectations for Wish, a movie that was only released about 16 months ago, and there's no way 2, 3, 5 years ago that Disney knew how it would ultimately fare.
It's inclusion here is not part of some master plan to nurture the property. It's just dumb luck that they decided to build a float for a flop and likely figured there's no sense trying to redesign something else from scratch.
Movies like Fantasia, Alice, Sleeping Beauty took literal DECADES to develop a following, fueled in no small part by theatrical re-releases and home video, things that no longer exists but were a highly important part of the Disney profit and distribution machine. Wish won't benefit from that for the same reasons Treasure Planet and Atlantis didn't either.
Maybe one day people will look back at Wish and re-evaluate the movie, but it's far too early to know if it will. The streaming numbers don't suggest that's the case either. Speaking of The Black Cauldron, Wish's domestic box office was comparable when you adjust for ticket price inflation from 1985.
As someone who is sick of the same half-dozen Disney/Pixar movies being used for everything in the parks, I'm not mad Wish is featured here. Better that than Toy Story again. When Pete's Dragon was added to the Electrical Parade in 1977 nobody knew it would disappoint either, but it became a staple of the experience and millions have been introduced to the character and songs from that parade since. Intentional or not, you get good publicity from being in a long running Disney parade.