I've always wanted to see the results of, say an 18lbs steel racing bike with modern components and rim brakes matched against a 17lbs carbon aero bike with discs. Same for a 10 year old top-of-the-line 16lbs rim brake carbon bike vs the latest disc brake carbon wonder bike. The fact that bike manufacturers are reluctant to conduct these tests caused me to suspect the results wouldn't be to the likings of their profit margins.
The modern bike industry is a scam so far as I'm concerned.