The reason i said something is because, to me, the most obvious difference between a classic VW and a modern one is the drivetrain: old VWs are aircooled, while new ones are watercooled. The drivetrain on fixed gear bikes hasn't changed that drastically, has it?

I think learning how to wrench on old bikes, especially fixed gear, does translate over to newer bikes.. simple things like changes in materials, sizes and geometry don't require learning tons of new things.

newer road bikes do have a lot of technology differences (indexed shifting, disc brakes, etc) but most fixed gear bikes don't incorporate much of that technology.. they don't have any shifting, and i rarely see any brakes