No matter what, people are going to still use cars because they are an absolute advantage over public transportation for certain use cases. It is better that the existing status quo is improved to reduce death rates, than hope for a much larger scale change in infrastructure (when we have already seen that attempts at infrastructure overhaul in the US, like high-speed rail, is just an infinitely deep money pit)

Even though the train system in Japan is 10x better than the US as a whole, the per-capita vehicle ownership rate in Japan is not much lower than the US (779 per 1000 vs 670 per 1000). It would be a pipe dream for American trains/subways to be as good as Japan, but even a change that significant would lead to a vehicle ownership share reduced by only about 13%.