Though I cannot qualify this statement, I believe that guys in the old days preferred big bikes. The theory was that a big bike goes faster than a smaller one, all things being equal. Horse hooey, of course, but that might explain ALL of the big frame set bikes I see.

Also, modern technology has made it possible to build differently. A wheel is still a wheel but everything else has pretty much changed over the years. Bike frame sets are no different, in my opinion.

As for looks, some of the new bikes make me drool! Of course, quite a few old ones do also.