I often compare rugs with cars. This seems strange but looking at it a bit closer it is a very good comparison. If you buy a regular car, it has lost it`s value within about average 10 years. It is a product you use and after its time it is junk. Same with rugs. Buying a regular persian rug newer production, indian average stuff and so on it is something you use and at the end you get rid of it ( :-) on ebay).
If you have a 30 year old car, well mentained and maybe something you don`t find on every corner, it is already something of value. The older it gets, the more expensive it is. Same with rugs. If you look at the prices of exquisit old or antique rugs, you see they have not lost much value, most went up in price. Same with high quality new rugs as was posted before by jahannandsons, little persia and rugpro.
You must be aware that prices of old and antique rugs are subjet of change with fashion in interiour design. Kashan and Meshed rugs with red, flowers and medaillon are very hard to sell today. They where the best selling rugs in the 1980 - 90, but almost unsellable today. So this is the chance to buy fine and well mentained Kashans at low prices. You never know when the price will rise again, but I think you will never get them cheaper than nowadays.
Geometric designs sell well all the time (Kazaks, Serapis and so on). Therefore the prices are still high.
Younger poeple never have been much customers to rugs. Usually it starts at ca. age around 40 years and up. Most customers in our shop have passed age of 50.