Hi all, I am getting into road bikes lately after being mostly on mountain bikes, and I have to ask you all, why are parts sooo expensive? (and it seems to be all about the parts when you talk to someone about road biking)

first, for the top quality parts, what causes them to be so expensive? As far as I can tell, they are made with standard metal machining techniques. Is there something else? Titanium? Where is all the money going?

second, what do the ultimate most expensive parts get you that the low end stuff doesn't? Durability? Smooth action?

or is it the parts makers seeing that people will pay these prices?

Thanks for entertaining my beginner's questions!