I suggest that it's all about the original plating process, the corrosion starts underneath the shiny chrome layer. My last 2 new chrome plated cruiser forks from eBay both pitted within 2 years, even after religious application of wax externally and fluid film internally.
Your old Schwinn probably had a much more careful plating process, keep it clean, store in a dry place, make sure any scratches are filled with wax. Spray a little corrosion protectant inside the tubes, and any place dissimilar metals meet (fluid film or T-9).