personally lose someone, no, but i've gotten the chance of being a citizen first responder to a lost of life one. i feel like your's and OP's response are because you've never seen or been impacted first hand what dying by car is like. it is usually horrific and violent that to be able to say those outweigh the time saved traversing the sprawled built environment created for the sake of those very same cars shows a lack of any lived experience. your argument fundamentally relies on the idea "all i know is cars, and there is nothing better". it's uncreative, unrealistic, and devoid of humanity. it's terrifying you and others with your mindset are on the road.
I think that in North America the deal is done, there is no way of going back this far down the path and private vehicles on the road are never going away until the fall of said civilization (or plan B: making the country dirt poor, but this may lead to plan A anyway)
And props for being a responder and seeing it with your own eyes. I actually think it should be more widely spread, showing it on the nightly news, etc. it’s an effective strategy to make more careful drivers.