Plated bullets these days cost more than coated with no advantage. Most FMJ bullets cost no more than plated so why buy them?
I wouldn't agree that there are no advantages versus coated - the coated are certainly a little dirtier in the gun and smokier (particularly with some of the hotter powders)... if you're trying to shoot rapidly early in the morning or late in the afternoon with low sun, the smoke can add some challenge. And, on the press, the coated often require a little more flare than the plated to seat without damage. But these aren't big advantages, and a lot of shooters don't want to pay any for the difference.
As for FMJ's, those have exposed lead bases. Some people don't want that.
Like you, I agree that the rise of coated had a big impact on the plated makers.