[ficke]

Any car can be "collectable" pretty much any air cooled Porsche is sought after now as Pmax mentioned.
But as for pecking order, older as a rule of thumb is better, or more collectable, unless your car has some special features as Xbrumossalesman pointed out, It is pretty much a nice used car in todays market, that is no longer dropping in price and is gaining in value but no where near the price of the new 911, so still a used car. The option for people who can not afford the new one.

So If you bought the car to drive then drive it. If it bother's you to put miles and wear and tear on such a nice car that is to much of a collectable to you, then sell it and buy one you are willing to drive.

If you bought the car because you think it is a rare and cool collectable, then it is to you and treat it as the rare and cool collectable you think it is and other people just have not caught on yet.

I think the main driver of the Porsche collectable car market is well "drivers" of their collectable Porsche, so if you do save it like the previous owner did, you are saving it for a future driver anyway. Kind of like saving your girl friend for that future boy friend.