Oh my! Do we really need all these new sounds? I usually use 2 or three pianos, guitars, strings, etc from each instrument category in each one of my keyboards and Vsts and I would say I still don't know most of them. Unless they really have a very improved quality I don't see the point but I'm glad it makes happy so many people. I used to be one of them.
That's pretty scary, if you add the cost of all those keyboards, then divide by the number of sounds you use!