I would argue it's often more about falling into the same trap as 'audiophiles' as it is about direct benefits. Few people notice the added weight from drinking 2lb of water but people spend hundreds of dollars shaving 1/10th of that from their bike.
It does make a very considerable difference, if you're serious about your biking, though. Plus, more expensive bikes are not necessarily lighter - there are many variables involved on the price (wrist comfort, seating type, suspensions, frame stiffness/weight, numbers and quality of gears, etc) - many more than the usual 'audiophile' choosing range.
But yeah, a lot of people buy expensive rides for the looks and have no idea what do do with them...
In my experience, it stops making a difference once you have to carry a 20 lb kryptonite chain to lock it. I just spent all that money on a light bike, and now it's 20 pounds heavier. I hate bike thieves.
Unlike audiophile "benefits", weight loss to cyclists is directly quantifiable in theory[1] and measurable[2].
It's true that it is usually much cheaper to lose weight on the rider than on the bike, but for some people it is probably easier (and more fun!) to spend the money.
[1] that's assuming your vary light, climbing the whole trip, and have a terrible power output of 250w and uses 3lb which is a fair amount and even then 8.5 seconds after a 2km climb.
A more realistic 400w + 120lb rider +3% grade for 2000km then a negative 3% grade for 2000km and a weight diffidence of .3lb for 300$. End result after 4,000km is less than 5 minutes wow that's worth 300$.
[2] 1 trip using human riders hardly qualify's as measurement. But even still measurement is next to meaningless you can detect cocaine on most people in an international airport that does not mean they have had anything but the most indirect contact with the stuff.
PS: Sure if your racing professionally then things change around, but that's a tiny portion of the bike community.
When you are out riding with your friends, you typically want to beat them to the top of climb. A 2km climb is fairly reasonable for that type of climb.
You are right - 200w is low - I just used the default values. If you look on Strava, most middle-of-the-pack people post power in the low 300watts.
1.5 kg is easily the difference between a < $1000 bike and a $2000 bike. Cycling (as a sport) has a lot of financially wealthy (but time poor) people (the same people who used to play golf). These people aren't interested in the cost effectiveness of an upgrade, just weather it will help them beat their friends up a hill on the Saturday ride.
Personally, I think using ~$200 carbon fiber water bottle cages to save 30 grams is a waste of money. But the truth is that the grams they save do add up, and the weight does make a difference on hills. If you don't care about money (!) then why not spend the money....
To chime in - offroading with a mountain Bike - if I take a drop > ~5 feet or so, the tires on my (former) $500 dollar bike would Taco.So yeah, there's a diff, and its not always weight.
For me the price isn't about the weight, it's about me commuting in a city with huge hills, rain, and long flat stretches. My commute goes up and down several 300ft hills and across a long bridge (Seattle to Bellevue). So I end up riding a road bike with a large gear range and disc brakes. This isn't easy to setup, and my components cost more than the frame. When you commute every day 45 minutes each way, it also makes sense to spend some money on comfort (I mean that's 400 hours a year you are on the bike). Most people do it when they buy cars, it's the same think.
It completely depends on one's typical ride. If you're climbing 10% grades all day in lycra, then 5 lbs makes an enormous difference. If, on the other hand, you're carrying a 10 lbs lock and 40 lbs of stuff in your panniers, then, yeah, the weight of the bike won't matter that much. In the latter case a heavier bike may actually be better.
As much as everyone obsesses over weight, it's not the only difference between a $500 bike an a $5000. The more expensive components are also going to have more-difficult-to-quantify benefits like fit and finish (i.e., look prettier). The higher-end components also work better: shifting will be much more consistent, bearings will roll more freely, brakes won't require as much force, etc.
This is analogous to a car magazine complaining about how a particular model has a "mushy gearbox." You can still drive it, but the experience isn't as nice.
Most 'serious cyclists' don't actually spend that kind of money on that kind of weight. Some crazy people do, but some people also spend $8k on a desktop PC.
In the range of most cyclists: having carried my $400 iron-frame bike up stairs and a friend's $1500 bike up same, the difference is certainly not "1/10 of 2lb".
