Your comment is full of factual errors, erroneous assumptions, and evidence of living in a privileged bubble.
Bicycles are not universally illegal on the sidewalk -- in fact, they're specifically legal on the sidewalk where I live, and yes it's in the US. Not that illegality stops people anywhere.
If you want permits, those are generally funded by fees. Talk about that, rather than a knee-jerk ban. As you've already indicated: Enforcement can be difficult. So how are you going to enforce a complete ban, anyway?
A lot of my money goes to things I don't like. For example, your protection by police, fire, military, and the courts. I'd very much like a refund on that. Just for the portion that covers you, you understand. I'm fine with it going to everyone else. Since you're just one person, that's well below your apparent threshold of 1% for number of people that actually matter, so it shouldn't be a problem, right?
Horses can be lawfully ridden on many if not most city streets, including New York City.
It is probable there is some motorized vehicle your son would be permitted to operate in Manhattan. Electric-assist bicycles are often legal on city streets. Not being able to ride an ATV is a consequence of regulation of vehicular traffic, rather than a blanket ban on wheeled transport, as you wish for RC aircraft. And certainly when your son reaches the appropriate age, he will be able to obtain a license to operate a wide variety of motorized vehicles in New York City and across the country. Again, regulation, not prohibition.
80% of the US population is urbanized. Suburbs are largely for a privileged class, and the extreme rural poor would generally be better served if they could live in a city.
Getting out of an urban environment requires the parent to be privileged enough to have the time to do it, and the money to afford the car and gas. You may think this is no problem for most of the people who can afford to live in Manhattan, but Manhattan is not the only urban area in the US. Banning RC aircraft from urban areas covers many high-population areas that I don't believe you have visited or understand in the least.
Try spending some time outside wealthy uptown areas for a while. There's a country full of urban areas you have obviously not seen or experienced. People living lives vastly different from your own. People you want to rip privileges away from because you think Manhattan is America.