I'm beginning to think that one of those older original or unrestored cars is worth only about 10% of its restored value...especially when you figure the cost of restoration.....you can put upwards of $30,000 in restoring a wood body car - & then find its only worth about that much!
Plus, some of the rarer, older cars are so rare that parts aren't available within the realm of everyday collectors budgets making their restoration more expensive but not driving their values up.
As an example, an MG YT Tourer which is probably the rarest of all WWII MG's is less valuable than TC's, TD's or TF's.
Just, my developing opinion....