- dipping rebar in epoxy is sometimes done, but a single nick in the coating causes all the erosion to concentrate in that one spot, so it can be more dangerous than just uncoated rebar
- galvanised rebar works much better than epoxy, and resists corrosion at lower pH levels than normal iron, but may result in more metal loss under some conditions
- sacrificial anodes (as per the article) can and are used, but exactly how is quite complicated: if they're embedded in the concrete, the zinc breaks down into substances that can weaken it
- concrete is naturally alkaline, with cement being manufactured partly from lime, and this protects the rebar, but too high a pH causes other problems in the concrete itself, so you can't just dump alkaline substances into the mixture forever
- you can apparently use fibreglass as rebar, but I have no idea if it's any good, or what happens to fibreglass if you leave it embedded in concrete for a century