I've seen this a million times. The clearcoat gets checks in it. Once you try and buff it out, it gets even worse.

Usually, repainting is the way to go. Check out the local Maaco shop. IT isn't the perfect paintjob, but if you do the basic sanding and the prepwork (fix any dents and scratches, and do most of the masking of trim pieces) they'll shoot the paint on. Make sure they have your color available. Or a very close color. For $300, it isn't a bad way to go. Better than spending $100 in materials, and six hours of time trying to bring back a dead paintjob.

The problem is, the basecoat/clearcoat combination is excellent EXCEPT when the clearcoat fails. The basecoat is not shiny at all, and can't be buffed shiny. Basecoats are dull by nature. The clearcoat can SOMETIMES (note the word "sometimes" with the appropriate cautions) be re-sprayed to give a decent finish for a period of time. Depending on exposure to sun and elements, it can look better than a crappy dull finish for a year or so. You can buy a can of clearcoat. Clean the surface of the paint with mineral spirits, and then hit the clearcoat on one panel. SEe what it does. SOmteimes it brings a decent shine back to the panel. But this is NOT a guarantee that it will work. I've seen it where someone sprayed new clearcoat over old stuff that flaked off, and the new clear peeled right up the same as the old did. It's some degradation of whatever keeps the two sticking together that causes them to separate.

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1992 940 wagon, low miles
as well as others.