I believe I agree. Density doesn't justify inaction or continuing along the path of inefficient individualized transit, so it shouldn't be used as a red herring

I believe I agree. Density doesn't justify inaction or continuing along the path of inefficient individualized transit, so it shouldn't be used as a red herring, but it's an important consideration that affects how people will use public transit. Regardless, there should be far more investment in transportation, because places in the US (among other places) that could be practically served by public transit still aren't, and you're right that investment begets clustering around transit hubs so it is necessary even before it seems ideal. As I said, there are quite a few more options nowadays for the last-mile: shared bikes, electric scooters/bicycles, or even Uber/Lyft/rideshare. This should further increase the viability of public transit even in areas of the US in which it wasn't previously viable.