The industry’s high point, in terms of unit sales, was the so-called "bike boom" in the 1970s. The boom ended suddenly when the industry reached a rapid saturation point and did not have breadth of product choices to sustain sales levels.
As we all know, an all Campy Schwinn Paramount was nearly identical to a Varsity. The collapse of gas prices (in real dollars) and the increased age of the boomers clearly had nothing to do with end of the bike boom.
That statement reminded me of an information plaque on the Blue Ridge Parkway that explained how the wolves had wiped out the buffalo in the Shenandoah valley. Coincidentally, the wolves suddenly did this just as the white folk appeared even though the buffalo had somehow survived with wolves for thousands of years.