Do they not make mens belts any more in which the buckle can be removed for another buckle?
Or is there some secret name that I am not aware of for a belt that has a removable buckle?

well, my husband got a belt like that and he changes the belt too. He keeps his buckle (very special one ) buys a belt in a special store and they replace the buckle.
Its a store were the fix shoes, belts, and sometimes bags too, special for leather.

I dont know if such a store is in the states, here in the Netherlands its very common.
We lived in Canada a few years back and they didn't know what i was asking then either, we fixed it in europe when we came back.

Good luck

An online search of "belts without buckles" brought results. Try it.

I did not bother to do a search because I tend to shop at the online stores I normally shop with.
It just seems weird that I don't see those any more at those stores. I thought maybe I was missing something,
such as a new name for them or that the rivets I see in the images might really be snaps.