Steel wheels stop OK if you're not riding too fast for conditions and the equipment you're on. Faster stopping allows faster riding, which leads also to more accidents of other types. Progress in equipment doesn't necessarily lead to better safety, but it's nice to be able to stop predictably!

We don't need aluminum rims to stop, just like we don't need helmets to ride safely. The stereotype of bicyclists was never someone with brain damage from hitting their head. Bicycling is now, and always has been, a very safe thing to do.