A custom frame built to do what I want it to do would cost $6k+ just for the frame and fork (I've gone through the options with my local builder). I'd be on a one-off nearly-irreplaceable bike, which would be on mind every time I dove into a corner or rode elbow to elbow in a race. My $7k factory bike can do almost everything the custom can do, but has the added bonus of being fixed/replaced by a Trek dealer anywhere in the world.