they have mainly gone up in value as things got insane with earlier, more prized vintage guitars.
Much like "last hired first fired" holds true in the job market, when the vintage guitar market 'levels off,' they will be the first to take a huge hit.
Woe is the person who pays a lot for a guitar they only sort-of like when it drops in value by half or more.
If you buy one, make sure it's worth what you pay for it to you, in terms of how it sounds. In other words, if it is only worth $100 tomorrow, would you still be glad you bought it?