I don't know for sure, but it may be because it was too expensive.
I know the original chromed finish used to wear off in time thus diminishing the look of the items, and possibly there was worry about children ingesting the paint that wore off?
The 4434 Silver Knight was a 25th Anniversary item (I think), and the silver finish is different to the original chrome finish. I hope it doesn't rub off in time. The 4430 30th Anniversary Gold Knight is similar to the 4434 Silver Knight. Both weigh slightly more than a Klicky wearing the same armour and no shiny finish, so I believe there is actual metal in the coating.
Has there been a 35th Anniversary set? I haven't seen one, but it should surely have been released last year.