1) Not all those are official editions. 2) None have features deliberately turned off. 3) Most , if not all, differ only in what optional components are installed by default, If you change your mind you can simply add whatever your missing - you can install Ubuntu, then add the bits that make it Kubuntu, then add Xubuntu etc.

But AFAIK they all cost the same price?

Well, I think the point of the article was not that segmenting made the product more expensive, but rather, you now have to sit down and spend some time carefully deciding which version you need.