Fairly common on bikes with braze on cable guides. I think I would just keep it clean , maybe wax the bike , keep a close watch on those guides. It will continue but hopefully you can keep it at bay for a while. The paint , from what I can see , is in nice shape so I don’t think it is ready for a complete repaint. I saw a bike that someone taped off a diamond shape area around each guide and filed , sanded , and painted a different color and it didn’t look bad . I have a Motobecane that suffered this problem and I just had the frame media blasted and powder painted and I applied the new decals. It ended up at about $200 total , but I only payed $20 for the bike and the paint wasn’t as nice as your bike.