modern chroming techniques are different for several reasons; firstly they no longer use hexavalent chrome salts in the process (good thing too, they are proven mutagens) and secondly the expectation is that anything chromed on a bike is only to last a short while anyway; cheap bike parts are the ones most often chromed and they don't last long at all so the plating isn't expected to either.
They had a wobbly phase just after the old processes got banned and they were still finding their way for sure. But today you can produce a good quality, durable chrome plate using modern techniques but to do so is simply very expensive. The corrosion protection originates in the nickel plating; the chrome itself is only few microns thick to give the shine, and does little for corrosion protection by itself. The Ni won't stick without Cu beneath, that is the only reason the Cu layer is there.
All this talk that 'modern chrome hasn't got enough layers in it' is nonsense; they just save money by making the Ni layer very thin in many cases. Good quality chrome plate has a much thicker layer of Ni and in the case of the best possible plating they polish the steel to a mirror finish before plating, put Cu and (several) Ni layers on, then polish the Ni to a mirror finish before flashing the chrome over the top of it. This extra Ni polishing stage is required for the best results because the Ni plate process shows every blemish in the surface tenfold; the thicker the Ni plate, the stronger this effect is.
To get chromework done to this standard is very labour intensive indeed, and therefore expensive. Go to a good plating shop and talk to them about what is possible; do however bear in mind that they are very good on car bumpers etc, and are less used to plating high strength thin-walled steel parts, that are susceptible to hydrogen cracking. They probably won't even know what hydrogen cracking is, in fact.
cheers
