It's all about cost. Those old durable sets were great when oil - the major determining factor in the price of plastic - was under $20 barrel. As the price went up, they sought out better deals.
But those from the '70s and '80s were very reliable sets, it was almost impossible to chip or break them.
Quite a disappointment =/ I'd pay a pretty penny for one of those old club sets. Do you know if they're even still made at all anymore?
I have a new - unused - windsor castle set.
I actually prefer the Marshall pieces to those. I want to find an old club set like I showed a picture of on the first page.