I think most people have a "thing" that they like to spend money on. I have a buddy whose "Thing" is watches and he will dump significant cash on a watch. I like a nice watch too but a few hundred dollars on a Citizen Eco Drive is my limit. I do not degrade him for spending 10K on a watch and my 3 hundred dollar watch is just as nice etc...
For the people that spend that kind of money on a putter it must be their "Thing".
I do feel their is a correlation to a degree between cost and quality. Functional replacement starts to work its way in their as well.