Stepped out of a coffee shop, got text from wife, grabbed my phone and got missed by inches by a kid on a scooter easily doing 25mph on the sidewalk. The text possibly saved my ability to walk in future by having me to pause just for a moment.
The problem is with bicycles being relegated to either the sidewalk or the main road with cars. I'm really not a fan of how cities create bikelanes by putting a line through the sidewalk and then nobody respects it.
I see the appeal in trying to ride fast, but it gets kind of scary. When I rode a bike I went fast outside the city specifically to avoid pedestrians.
I was 3-4 feet from a building corner when someone raced around it on a scooter. Amazing to me the complete lack of both self-preservation and respect for others.
On the other hand, kids have always been stupid. We've just given them new, more powerful ways to abuse that lack of awareness.