Opinions vary, but mine is that given how long the frame has lasted, how much protection does it really need? Keeping it clean helps, moisture can build up in dirt. Conversely, greasy dirt actually excludes moisture.
I wouldn't repaint that frame. If you had it apart, I'd consider giving it an oxalic acid soak for good measure, dry it off really well, squirt some wd40 in the tubes, might as well wax it then, a lot easier to do than with all the parts on. A lot of wax will have a light abrasive and may help a bit with oxidation. You can get a little more aggressive with different grades of rubbing/polishing compound, I'd proceed slowly/carefully with that,though, experiment on low visibility spots. Don't want to rub off the paint, which is easy to do inadvertently on high points, like lug corners/points.
Others may advise differently, and that doesn't mean anyone is wrong or right. But I'll bet most would agree that this bike is a long way from needing a repaint. It is amazing just what a good cleaning can accomplish. It won't be perfect, but there is nothing wrong with patina.
Very cool frame with the long point lugs, cutouts, etc.