If you see amazing clothing, either someone is really good at poly modeling or sculpting clothes by hand, or more likely the clothing was created in Marvelous Designer, which is a powerful software purely for clothing design:
The difference with Marvelous Designer is that it is a fashion-design software of sorts, that relies on clothing pattern and sewing-like concepts, rather than modeling polygons around a character. Basically, clothing is created in Marvelous Designer much like fashion designers create clothes, so of course it is more powerful for that than the techniques in Max, Maya and so on.
Most Pro 3D softs have cloth and hair that works. Cinema4D for example has both. So do Max and Maya.
There are usually also various plugins for cloth, hair you can use.
As for people knowing modeling, rigging, cloth, hair, texturing, rendering and so on - yes, good 3D generalists typically know all that stuff and can do it pretty well if they learned hard and are talented.
Some people are specialized in 1 or 2 aspects of 3D - specialists. Others - generalists - often try out and learn almost all aspects of 3D to some degree.
If what is being done is just concept work, it is probably OK to use just about anything that works - character generators and such - and delivers the needed result on time.