there are some interesting posts and obviously layers of complexity. I don't think we have laws like this in the UK.
A couple of observations though. As the need for a replacment rear bumper for example is not due to any sort of failiure and not covered by manufacturers warranty but instead due to a collision, would the manufacturer have any obligations ?
Second thought is that as Karmann "went bust" and are now being bought by VW, then Chrysler may have no access (or contract) to get new replacememt parts made and may need to set up new manufacturing facilities.
What I do know is that getting a rear bumper in the Uk is surprisingly difficult and it is only 2009 !

Looks like an interesting debate