In my opinion, single stage paints are very fun to work with but you need to know how they work so that you can know how to take care of them. Single stage paint jobs require nourishing from time to time and act like leather. This is a simple fundamental most people don't know about as single stage is quickly becoming a thing of the past.
For example, if in theory you were to leave a piece of leather out in the elements, eventually it would dry out. But if you every so often went out and moisturized this hypothetical piece of leather, it would maintain its supple characteristics. And of course if you indefinitely left the leather out in the elements without any protection, eventually it would crack (this represents a single stage paint job that is too far gone and has oxidized to the point of no return and lets hope your car isn't the case.)
Single stage paint is pretty much the same as leather, characteristically speaking, in that the two are somewhat porous and can take in products.
The absolute very first thing you'll want to do is to nourish the paint with a feeder oil such as Meguiar's #7. (Of course ater cleaning debris off the paint first.) M07 will soak into the paint and begin to condition the paint just like my leather example. Remember that single stage paints are not sealed with a clear coat and consequently can take in products that are applied onto them.
Remember that any information about paint work that you will find in regards to modern day base coat clear coat paint jobs will not be applicable to single stage paints; you need to understand this.
I'm not at all saying what you have done with this car is at all bad but if you REALLY want to bring the paint back to life I'd recommend reading over Mike Phillips' guide to restoring oxidized single stage paint. His article is super in-depth and encompasses how to bring paint, such as yours, back to beautiful quality by using the
right products and techniques. It is often someone such as yourself believes the paint is shot and requires a repaint to look beautiful again and although this could be the case, I have a feeling if you follow Mike's guide you'll be solid with this car.
At this point with your vehicle, the paint could be in an unstable state as you mentioned the paint is getting so thin. If this is a confirmed variable then you will probably have paint that looks nice for a while and then reverts back to its oxidized ways fairly quickly. Even after following the guide I linked, you might be running into this issue but I say it is worth a shot. Though there is also the chance that you can bring this paint job back to looking and staying excellent if you follow the right procedures.
The last thing you want to do is break out a buffer and it is good that you recognize this.
The bottom line is that your paint is heavily oxidized and yeah if you use a product such as you did here, it will look nice for a while. I'll bet that the paint returns to an oxidized state in the near future as you haven't nourished the paint but have simply masked over the problem. I know you love this car and I simply had to write this all for you. Maybe you don't want to go through the long process that I've sort of explained but if you want to preserve this vehicle I strongly recommend you check out the link below:
Here is the holy grail link for single stage paints: https://www.autogeekonline.net/forum/how-to-articles-by-mike-phillips/25304-secret-removing-oxidation-restoring-show-car-finish-antique-single-stage-paints.html
You know what, I'm going to steal some of Mike's photos and link them below. I'd like to think he wouldn't mind.
1972 Lincoln Continental Single Stage Before:
After:
1960 Ford Ranchero Single Stage Before:
After:
And Of Course a 1972 Mercedes-Benz 280 SE Single Stage Paint Hood Before:
Hood After:
This is what Mikes client told him about the car before performing a miracle on the paint: "He told me the paint was oxidized, especially the hood, trunk and roof. He also told me he took it to a local body shop where he was told the paint couldn't be saved but they could repaint it for around $2000.00 but this would not include removing all the chrome and stainless steel trim, nor the bumpers or emblems, basically an entry level paint job."
I hope these inspire you to think that maybe if you follow the right steps, you can bring your car back to its former glory. Here is another article to look at:
https://www.autogeekonline.net/forum/how-to-articles-by-mike-phillips/66800-4-steps-restore-single-paint-paint-1972-mercedes-benz-280-se.html
(None of these pictures are mine but they prove that Mike's methods work and the secret becomes apparent once you read over his articles) I've worked on single stage paints many times but I wouldn't consider myself an expert but I'll say that the information I've outlined here is regurgitated from Mike who is an expert. I've used his methods and had excellent results.
This is the right way to do it though and I think you'd be hard pressed to find any better information about single stage paint. I hope this helps someone else out there in the future.
Good luck