My guess is that the widespread move to matte black bikes from all brands means some chrome stuff is a thing of the past.
The painted versions of the Springfield still have chrome lights but I think the fork legs are wider on the Springfield than the Chief so the frame won't fit. And because the Springfield comes with the lights as stock, they are spare parts and not accessories, that means every piece is a different part number and the price sky-rockets.
Pablo referred to @dieselgman - but a typo got in the way.
I think because now no new models come from the factory without those lights except the dark horse, which you really wouldn’t put chrome light bars on. So there’s not much call to sell them as a set anymore. You can still buy all the pieces individually, but that ends up being more expensive than the whole set that your part number is for. I did find it on amazon and cheapcycleparts both still in stock though, so you can check both those sites.