Wish I knew someplace good to buy single-stage paint economically

Kendog 170 said
I swore by PPG but I painted my Ragtop 3 years ago single stage Black and it keeps starting to fade on the topside. I have to polish and wax quite often. I had Imron single stage black from 1985 -2019 and it never dulled at all.

I wonder if it was a synthetic enamel? Those paints would oxidize in like a year or two.