as usual, this debate is semantics. weight does matter.

to what extent it matters depends on each person, what they are trying to do on the bike, and how much weight. only a fool goes without water during the summer, so most of us gladly carry 3 pounds of water. yes there is a noticeable difference between a 18 pound bike and a 38 pound bike. the difference is obviously less as the weight reduces further to 17, 16, 13 pounds. I doubt it's diminishing returns, every pound probably matters the same, but the pounds do become harder and more expensive to lose.

for most of us, weight isn't the most important thing. we achieve what we achieve based on our endurance and power on the bike.

for those competing, if they are competitive in their group this implies they are doing the work necessary and have the innate physical gifts required to be a peer of their opponents. thus weight matters more for them. all weight carried by the bike-- their body weight, the bike's weight, all of it. improving themselves still matters more than improving the bike, but because they are in a competitive group, they need every advantage.