There was debate on the team back in ~2009 over changing the query params -- when you estimate how much bandwidth and disk is consumed per day at the scale of Analytics, just for the difference of a character or two on a handful of query params -- even well over a decade ago, it really was astounding.

The migration would never be total, though, because more than a few users had copied the analytics script to their CDN or were in some way depending on a local fork of it. Some backwards compatibility would need to be maintained, perhaps for as long as the product exists. For this and other reasons, changing the params (and supporting both, indefinitely) wasn't pursued.