[pmontra]

Your points about the zillions of rim brakes bikes sold at 100-300 Euro price points are definitely on spot. They don't need performance, those brakes are very cheap, they are easy to maintain, they'll last forever in the market IMHO.

However I'm not sure I understood your first point about disc vs rim brakes. Rim brakes are lighter but disc brakes brake better, in a shorter span and under any circumstance, even in the rain when the rim is wet and a rim brake takes a little to warm up and make friction on the rim. Furthermore wheels and bikes are at 6.8 kg even with disc brakes now. That's why every pro rider started using them when they had a choice. There was a short while when they were kept at hold because of concerns that the disc could hurt riders in group crashes (they don't have that problem in cyclocross or MTB,) then concerns about weight and aero, but given the average speeds they are doing at the Giro in these days I'd say that it is all well in the past.

I'm no tour de France rider but on a steep and long slope I rather use my disc brakes than the rim brakes of my previous bicycle. It was a good bike with much better brakes than the vbrakes of the bike I use for touring with bags but disc brakes are on a different level.