Everything but the frame sets, Regal saddles, and Giro-Italia bars. Sure - I got along just fine with the old technology, but folks got along just fine without trains, telegraphs, and refrigeration, too.
Modern technology has given us better drive trains, better tires, better wheels, and better controls/cables/housings.
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"Love is not the dying moan of a distant violin, it’s the triumphant twang of a bedspring."
S. J. Perelman