R,
Chrome cannot tolerate flexing-bending-warpage-shrinkage-expansion, of which plastic has proven subject to exhibit. It's much, MUCH cheaper for fomoco to go for the short term gleam of covered plastic, vs a much more longevity life span of chrome over alloy. After a couple tire rotations, getting whacked by rubber mallets and the like....you get the point.
Let's be truthful here please.