Lets compare it to the automotive Blue Book, which is pretty accurate and see what the differences are.
Why is the automotive Blue Book more accurate than the bicycle Blue Book? I think there are two reasons.
- Statistics. There are lots of cars sold every week, averages out to around 800,000 per week.
- Those sales consist of relatively few models. I'm guessing that the vast majority of sales cover fewer than 500 models.
- The price of sale is relatively accurate, centrally recorded, and publicly available through DMV records.
So without getting needlessly mathematical, I assert that the average price of sale is statistically significant for most models.
Bikes have fewer sales, there are lots of manufacturers and models, and there is no central source of data for the sales price. So it is a lot harder to come up with numbers. You can cross your eyes and compare it to buying a 1922 Ford pickup. Certainly it has a value, but there are so few sales that it just boils down to what an individual buyer is willing to pay.