Is there any way to restore trim when it's gone this far? I've rubbed the crap out of it with 0000 steel wool already.
Sure, a pro can fix that easily, I'm 100% confident it can be brought back. You have to know what you're doing, and you have to have the right knowledge and tools. Some SS is actually "flash" chromed. You need to remove that first before you can even get to the metal. Smartin (Adam) knows this. If you want to learn to do it, you need to start with a small piece. The bigger the piece, the more difficult it is.
I typically put SS on the buffing wheel. Makes it shine like new, but it can get away from you pretty quick if you aren't careful... throw it into the wall and twist it into a pretzel, or worse, into your face.
Put one of these on a stand with 10"wheels on both sides. Put a hard buffer on one side and a flapper buffer on the other side. Buy some good buffing sticks and go at it. But like Roger said - be careful. I slung some side trim about 40 feet into the yard! https://www.harborfreight.com/8-inch-bench-grinder-buffer-94327.html
Being a Riviera, (I'm assuming that is what you're working on) there is a good change that stuff has a flash chrome layer on it. Possibly not, depending on what part it is. Shoot me a message if you'd like me to take a look at what you have.
Find a good guy that can restore them. They can perform magic. Be very careful doing it yourself. You can really get hurt and so can anything in the vicinity of the wheel. I have tried and “launched” things across the garage. Decided it wasn’t a task for me.
Right, flash chrome, it sucks. You have to know where it was used, that was the problem I had, too. I think like Skylark fronts are "flashed" and rears aren't. I'd agree with Dave. I bought all the stuff to do it and read up on it. I did a couple pieces, it was a ton of work and I got pretty good results. Then I had some rough pieces, so I sent them out. They came back way better than what I could do. After that, I just send the stuff out now. Somebody here posted a really neat pic of a cut from buffing SS. A headlight ring, or something.