Look at what Disneyland is doing for this holiday season. Paint the night will be done nightly and Disneyland forever fireworks will continue and their holiday fireworks show will not be shown this year.It's a very popular parade yeah I'm pretty confident more people care about seeing it than have even noticed the garland.
Also if you move the Once Upon a Christmastime Parade to day for the whole Christmas season you're taking away one of the major draws of MVMCP. I don't see that being popular.