There are two large swiss families. One is the traditional emmentaler that comes out of the Jura alpine-type (gruyere) tradition. Two is the branch that is more modern and is a crossover that happened when the Dutch practices meshed with traditional emmentaler. In this second branch, there are tons of variants... such as straight gouda with PS, or straight gouda with PS where the curds aren't washed. Or one specifically crafted for huge eyes (leerdaamer), or these other more modern variants.. jarlsberg, maasdam, etc. Confusing the situation even more is that some culture blends are meso+thermo, where the thermo is also a SLAB (usually TA, so not true bacilli thermo like is used in emmentaler).
And when you get to the baby swiss approach, anything goes because that's also a more modern take.
End point: variation due to historical practices and cultural changes over time. Cheese makes for some interesting cultural anthropology
