In the United States, the bike boom of the the early 1970s coincided with most of the large cohort of baby boomers being teens and young adults, along with factors such as the OPEC oil embargo, rising environmental and health awareness. I believe, youth cycling then, as compared to now, had many more young people on bikes. Where I live there are plenty of kids but it's rare to see any on a bike around neighborhoods. However, there is a cycling boom of sorts going on in many urban areas of the USA with conventional bicycles, e-bikes, and e-scooters being promoted and adopted, particularly by young adults living in urbanized areas. However, I don't think it's nearly as widespread across the population as the boom of the 1970s.
As part of the growth of cycling, the attempts to place large numbers of rental dockless e-bikes and e-scooters are being fueled by speculative investors hoping to capture the attention, use and dollars of the population. So far, the results have been mixed both in adoption by riders and the success of the companies involved.
You won't get any argument from me regarding the value of bicycling as both transportation and recreation. We need a huge boom in cycling infrastructure to make cycling in general take off but the competition for infrastructure resources is fierce everywhere so I'm not too hopeful to see the boom anytime soon.