One holster "fits most" doesn't work out well.
I agree, but I think he's talking about holsters that fit the same series weapon.
Like crossbreeds will fit almost all glocks because on a glock the back of the slide & grip doesn't change. Just the length of the grip & slide. So they all fit the same in the holster. My Safari land holsters are the same. Mine will fit my G22 or a 17, 19, 23, 26 & 27.