Kirk's just steamed that we've already figured out a cooler space suit than his.
It can be argued we spend so much time focusing on what astronauts do once they get in their spacecraft and make it up in space, we forget the thousands of hours that go into testing everything the astronauts will touch, do and even wear. The following video is a fun look at early spacesuit testing, showing different models being put through their paces.
Working is microgravity is not easy, and during the Gemini space program in the 1960s, there were concerns that EVAs might not be a safe way to work in space. Advances in suit design and EVA techniques ultimately made it possible, and now scientists want to make things even easier by getting the suits to simulate Earth gravity.