A few weeks ago now I caught up with bloke on my way back from York. He was riding an 80s racer lookalike, and it was absolutely knackered. The rims were rusty and buckled. Every few pedal strokes, the chain would slip, one pedal was at an angle of about 45 degrees to the crank (rather than the more traditional 90 degrees) and the other clearly had a severely bent spindle. There was one alloy mudguard that rattled and buzzed against the tyres, and both tyres were rather soft.
The thing is, I drafted this guy doing a good steady 20 mph for a couple of miles.
Put him on a decent bike and he'd be seriously fast.