I have the same on my 2014 car, I had it "detailed" last year and he polished it up looked great but over time it came back.
So I suspect polishing is just a tempory solution. However that particular "detail" was done by a pro detailer but it was the most basic detail option he provided so it could be that he only gave it enough attention to provide a short term solution!? I'm not really sure, but I agree with your concerns it looks rubbish, and looks like the issue is internal rather than on the surface.