Rather than ban them, just require them to show the poor crash test scores. I wonder if insurance companies charge motorcycle riders a lot more for personal injury coverage as compared to car drivers. That could also happen with unsafe cars making them not so economical in the long run.
They've had crash testing and crash safety scores for decades, both the government and the insurance companies and the results are publicized, widely available and manufactures that score well brag about their ratings. Volvo built their entire reputation on building safe cars and they were very successful at it. They were decades ahead in the 1960s, already offering 3 point seatbelts front and rear, crumple zones, steel safety cage, side impact protection, padded interior parts, all many years before anyone was required to provide these things. They have always been quite expensive cars and yet they were very popular, my area was crawling with them in the 70s-90s before they tried to become a luxury brand and handed nearly their whole market to Subaru. Not everybody is as stupid and helpless as a few people here seem to think they are, not all of us need to be treated like a small child and have these choices made for us by the nanny state. The free market works, government regulations largely make things worse, not better. They take away choice and stifle innovation. Maybe some people would prefer to live in a world where the government controls every aspect of their lives and makes all of the important decisions for them but I do not, to me that is the description of a dystopian hell. I HATE regulation, I HATE rules, I HATE being told what to do, and I will aggressively push back against anybody who tries to control me.