Originally Posted by Jughed

To be fair - this was a full race spec bike vs a full race spec bike - fenders and racks are not part of that. And you can find modern bikes without all of the proprietary parts/integrated everything.

Gearing and shifting were the main differences, followed by tires and wheels.

A fit ex pro 300w+ rider couldn't get the old bike up the hill, the new bike allowed him to spin right up. Meaning us less fit, non ex pro riders have more of a chance to ride more places on a race style bike.

Here is the kicker for me - all the marketing and hype about speed. X watts faster, aero this, speed that. 50 years of development = 6% speed gains. Much of that is from tires and wheels, and some weight. 6% for an ex pro going full gas. Less for us normal duffers.