That's great. You can also go back in time 30 or 40 years and see almost nobody wearing seat belts in cars. And if everyone is stupid, that means it is safe!

25 MPH without any form of cabin/canopy is REALLY fast (especially for a stop-go environment like a city which is all that anyone actually cares about in these discussions). Quick google puts random cycling oriented websites saying road bikes average out 13-17 mph. So we are looking at almost double the speed of where people already SHOULD be wearing helmets because one good fall means they need a hose to wipe your brains off the pavement. It doesn't happen super often, but that is more because... cars do a good job of taking out cyclists anyway.

And whether you and your 50 year old buddies personally care: This impacts adoption. Because renting out electric scooters is already a giant mess and if people hadn't universally decided they hate those, there would be a lot more dead tech bros on the streets (... which, for legal reasons, would be bad). Which is the issue. Because people who live in an area already have cars or know how to use public transportation or are hardcore cyclists with heads made out of reinforced titanium. People on a holiday or work trip either don't even consider it to be an option or... question the stupidity of the people flying past at 25 MPH without helmets.

If there were an actual culture of safety and a way to get a helmet that wasn't already cracked and dented: We would see a lot more electric bicycle rentals and people probably would care about those. As it stands, they are a niche item that is often associated with "he was taken from us so early..."