No one set up is right for everyone. I can see a fixie being good for bike messengers and for people riding and from school or work over short distances. I can also see it working well for people who ride regularly is extreme cold (below 0F). Sometimes, riding a fixie may not be a practicle as a geared bike with a freewheel, but it's worth it nonetheless because some people just enjoy riding a fixed gear.

On the other side, all those other "extras" we non-fixies use serve a purpose (if they don't on your bike, you should take them off).

In the end, it's all a matter of what fits the way you ride, and what makes your ride fun.