There were tons of younger riders both in the 90s and 2000s- one wave from mountain biking (when Americans were good at it, so there was enthusiasm) and fixies, which were cheap and cool and durable.
Fixies especially seemed like they would usher in more urban cycling (especially with people switching to singlespeed, but keeping the cool look), and messenger culture was a thing. There was no specialized equipment, except for perhaps tight jeans and moustache (optional for women).
However, no matter go interested people are, eventually reality hits you like a truck, or car door as the case may be, and your third bike gets stolen, and you get sick of it.
People would definitely use the infrastructure- there's no shortage of people who like to rides bikes, but are sick of dealing with crazy drivers and potholes and car doors and fedex/prime trucks parked wherever in the middle of the road.
