I'm sure there are cases where it *will* decrease the longevity. Look at how some people claim that not claying will do the same thing.
BUT...I can't really think of one single time that having an underlying application of glaze, or having not clayed, made any difference.
But that's with waxes.
Noting that many "waxes" are sooo synthetic as to be basically "sealants" (and noting all those scare-quotes when I use those terms :chuckle: )...I've had sealants refuse to bond to certain underlying products. In those cases the sealants basically wiped right off, or left a smeary mess. When I let such situations sit for a few days, the product did buff off pretty cleanly, and things seemed basically OK, but the sealant didn't last very long.
So IME glazes and waxes generally work OK together. But with sealants you have to be more careful. Not like you *can't* use some underlying product with sealants, just gotta choose the right one. Consider that may product lines (BlackFire and Autoglym come to mind) have systems where a "glaze-like product" is used before the sealant, and those systems work OK.