too much fascination with light rail pretty much indebted most transit authorities to large bonds to pay off and very high maintenance cost. All that money would have been better spent on improved bus services but unfortunately trains are "sexy" whereas buses get a bad rap; loser cruiser and so on.

Post WW2 government programs encouraged vets and similar to move to the suburbs and highway programs gave way to a very strong automobile industry.

The top it off with more restrictive zoning laws in the US, where compared to Europe you much much less likely to see mixed use of land. in the US land zoned residential is usually kept well separated from industry which does add in commute times and needs for alternative transportation. Throw on that fuel and car taxes have always been cheap