Originally Posted by greenstork

C'mon, need is a relative term. Could we all get by with downtube shifters? Yes probably, we don't need integrated shifters or barcons. Do we really need 9-10 speed rear cassettes? No, we don't really need all of those gears. Do any of us really need $1000-1500 bikes? No, probably not, we could easily get by with much less.

If you live in a wet environment, then disc brakes have real advantages. If you don't or if you don't often ride in the rain, then the because of the cost & weight, disc brakes are probably unncessary.