> People didn't put lights on their bikes at night until about 15 years ago when low-weight, bright LEDs became cheap and ubiquitous
Perhaps this is different in the US, but in the UK people were definitely putting lights on their bikes way before then, because if you didn't you were liable to get stopped by the police. Having a light on your bike in the UK has been the law for at least 30 years.
A light, maybe. Now it's not uncommon for a frequent night biker or city bike commuter to have several very visible LEDs on their bike and gear -- a far step up from the dim battery powered lights of 30 years ago.
Perhaps this is different in the US, but in the UK people were definitely putting lights on their bikes way before then, because if you didn't you were liable to get stopped by the police. Having a light on your bike in the UK has been the law for at least 30 years.