The most valuable bike is the one you use everyday, and for many of us it is a bike looked down upon by bike snobs.
I read an article about the Kronan, the new production swedish army bike. The founder of the company compared the Kronan to the pencils used by Kosmonauts. The story is, the first astronauts took pens with them to fill out some forms or check some checklists and they discovered that ball point pens don't work in space, so nasa spent 17 million developing a zero gravity pen. The soviets heard about this and thought, oh well we'll just use pencils.
The old bikes we ride as those pencils, they work just fine. They could be lighter or faster or be $4000 more expensive but they don't to be any of these things