Projection mapping technology, like any other technology, evolves. Scalable Display Technologies and 7th Sense had a booth at Infocomm 2023 with a technology of projection mapping on moving 3D objects.
A little more on it here:
https://7thsense.one/story/showcasing-unscripted-live-projection-mapping-moving-3d-objects
A short video here:
Scalable Display Technologies has some work on its website related to parades but not specifically projection mapping. But together with 7th Sense it's at least something that could further develop.
For a few reasons ideally the projector works from the float vs from a distance, but I don't think we've seen an indication that we're there yet. It's a technology that could have more immediate use in an attraction or live show with fixed spots, but it's worth at least knowing the technology is evolving and could have more applications in the near future.