In the end, I don't think it's that people don't remember the names of critics, it's that they never bother to learn them in the first place. Most people don't care, and that's perfectly fine - you have to be pretty deep into a field to care about its criticism in the first place. However, it also doesn't discredit the critics' work or criticism in general. Being famous doesn't make you right nor does it make your work more correct, after all.
In American society you could point at Edgar Allen Poe as someone who is only known for his fiction and poems, but who was a prolific critic in his day. He likely made more money as a lecturer than as a fiction writer in his later years. This has been researched a bit but sadly there are few texts that survive of those lectures, just newspaper opinions and advertisements about the lectures.
This one is one my personal favorites from the ones that weren't lost...
I'm not nitpicking, by the way, just enjoying the piece you shared.
I think about the only "art" critic of any kind that comes to mind quickly is, um... I'm embarrassed to admit it... Roger Ebert :P
Seriously though: I'll bet money most people who know names of painters or writers don't remember the name of any critic from those fields.