This is all a little skewed. For example, there was a time when you could get a Tioga disc wheel new for £25 when Madison sold off Thier old stock. I've seen Chris king/wtb headsets sell for under £200. It's easy to overinflate that value of something, you only have to look on eBay at the ridiculous bin prices for common tat, let alone rare stuff.
What are a lot of the parts rare? Pedigree and minimal numbers made I get, but a lot of the retro stuff is rare because it was poorly designed and under-engineered so they often broke. Some of it did look good though.
Onza white porcs £10ea on special etc. This thread is more about showing how things can and have changed with the value of retro parts. We all know you can build a retro bike very cheap -£100-150 but i never had a clue, as i suspect many of us didnt, just how pricey a top end ‘iconic build’ can be. Significabtly MORE than a modern halo bike £7-10k. Lets not forget the modern has a crazy high depreciation rate. A top end original retro like a Klein Attitude or Cunningham starts to make sense, not only as a great rider but as a safe investment 
