Originally Posted by
Garfield Cat
Apparent difference is the key issue here: some but not all bike manufacturers get input from the pro riders. For instance, the head tube and fork design has changed just in the last 10 years. Those professional riders can tell the difference when racing down the Tourmalet at 50+ miles per hour while negotiating the various switchbacks. Also the grand tours with its many stages means comfort versus stiffness is considered. Continuous seattube is another example.
Not all riders will take their rides to similar conditions as those found in the Grand Tours. Not all recreational riders need to equip themselves as if they will be like the pros.
Also keep in mind that the grand tour riders are likely to have spare copies of at least two types of bikes. They're optimizing durability for a much more limited purpose than year-in year-out usage.
We also have to keep in mind that grand tour racing is to a major extent a marketing event for the sponsors. So claims of significant performance gains from very expensive features should be taken with a grain of salt.