Within the world of go-fast or go-far riding, yeah, they do, with real measurable changes and gains up through probably $6-7.5K USD. For most riders, going abo

Within the world of go-fast or go-far riding, yeah, they do, with real measurable changes and gains up through probably $6-7.5K USD. For most riders, going above an entry level carbon fiber bike with Shimano 105 components and alloy rims is probably overkill. That price point is between $1500 and $2500US, depending on manufacturer and other options. If you're a larger rider, getting a better grade of carbon frame is worth it. I'm about 98kg, so I took that option. My bike was $3500US, but still with alloy rims. Wheels matter a LOT. The next step up in the Specialized line that year was exactly the same in all respects except wheels (carbon, aero) and price ($5,000US). The other thing you see in nicer enthusiast bikes is electronic shifting. This adds, say, $800 to $1500 to the price vs. an equivalent cable-pull bike. It sounds insane, but it's really quite nice -- and never goes out of adjustment. Disc brakes are taking over as well, but still command a slight premium. I don't have them because I live in a flat place, but if I lived in northern California or Colorado, they'd be a no-brainer -- they work WAY better on long descents or in the wet. Oh, and if you want titanium instead of carbon, well, the whole game STARTS much higher. The most common ti frames I see are from a company called Moots; entry level for the frame alone is about $4000US -- more than my bike was originally. Obviously, I don't see ti bikes except under fairly well-heeled riders MOST of the time (there are exceptions) -- but I see lots of normal middle class folks on $2500-$4000 (retail) bikes. That's kind of the default in the groups I ride in. Going higher is possible, but of limited utility. Going lower means you have a bit less fun, honestly. They didn't all pay full price or buy new, but that's the grade of bike around me on most rides.