There was a thread about this a month or so back, but in brief, you have to make a distinction between avant-garde cooking and pretentious nonsense. The line is not absolute, to be sure.
What you're talking about with the chowder is what's often called "deconstructed." We discussed this term at length in the other thread, and I won't repeat. It's also very questionable as to whether this should or should not be called "molecular gastronomy" anyway. But let's take all that as read, for a minute.
Suppose this is being done very, very well, and set up in the context of a meal that is also very well constructed and coherently thought through. In what way could "deconstructed" chowder make any sense?
One way would be to think, as a cook, about what "chowder" is, what it means, to the diner. So here we are in Boston, where chowder is a pretty well-known thing. There are longstanding fights about it -- no tomatoes, ever, in Boston. There are points of more minor disagreement: how much potato? salt pork or
bacon, and how much? can corn go in with clams and/or fish? can clams and fish go together? should it be thin or thick, and how thick, and what thickener?
Now take the whole dish apart and put it back together in a way that asks the diner to contemplate these questions himself. Not answer them, but think about them. One way to do this would be to take the various pieces apart and serve them in a peculiar fashion, for example upside-down: stabilize the liquid soup as a mousse, let's say, and put it on top of a clamshell filled with fish braised in clam liquid, and garnish with
bacon fat turned into a powder. Ideally, a bite including all ingredients would taste exactly like excellent clam chowder, but feel and look utterly different. The diner is asked to question just what "clam chowder" means here.
You can also use shock tactics in the same pursuit. Serve perfectly recognizable clams that are actually corn, a cream soup base that is actually pureed fish and clam, and so on, and then garnish with something apparently totally inappropriate --- like a single wedge of cherry tomato.
It's an aesthetic, intellectual game, at base. If the diner is stimulated in a wide range of ways, it's exciting and fun.
Now let's serve "deconstructed clam chowder" at a third-rate restaurant where it's on the "starters" menu at $12. Have two OK clams in a bowl, steamed, sitting with a piece of
bacon and a potato, and on the side a little pot of cream soup base to pour on top.
This is pretentious nonsense, unquestionably. But do you see that they're not the same thing?
Well done, avant-garde cooking is worth doing, but not to anyone's taste all the time. That's part of its point, really: if you ate it all the time, it wouldn't refer to anything else, and would become silly and pretentious. But on the other hand, avant-garde cooking is not superior to other cooking, and those who lionize it often don't see this.