I've never sought out or bought an old bike.
All of my now C&V machines have gotten that way through attrition having been built new "back when" for a specific purpose and proven useful and/or versatile enough to remain in service while others are long gone. The only one of the sold-off that I'd look twice at now is a '74 Raleigh Pro MkIV, but I'd just convert one to fixed gear use if I ran across it in my size in good nick at my price.
-Bandera