It's an engineering problem that may not be easy to solve.
The issue will be related to time, and environmental storage conditions. The time factor in this case is in decades. If the issue first became noticed in the 60's, I'm sure they would have tried to fix this. In order to do that, they would have tried other paints or coatings, hoping to find a good one that would last indefinitely. Unfortunately, this creates a new problem, in that you'll need to come up with a test that will give you a reliable prediction of the long term performance. They can't wait decades to do the test, so they need to come up with an "accelerated" test for this that could be completed in months. In industry, this is done all the time, but it's not always possible to come up with a reliable accelerated test, and you won't really know how good your test was until the full time has actually passed.
Accelerated testing usually involves changing some environmental factor dramatically, in order to reduce the time for the defect to occur. You can see where this is going. How do you make an accelerated test if you don't really know what factors affect the problem. It's another educated guess you have to make. All the testing in the world doesn't help, if you're not testing the right thing. That's just the way it goes sometimes.