I've seen it suggested that car-dependent suburbs were a deliberate way of preventing blacks, immigrants, minorities and the urban poor from being near the mostly white middle class.
I think that's more true now, where suburbs restrict bus routes, than it was in the past
I've seen the claim, too, in connection with the end of trams in L.A., & not recent. The suggestion was a shift to buses would help keep blacks out of more affluent neighborhoods. (How, exactly, a change from train/tram to bus would achieve this wasn't explained...tho AIUI, reduced service was a factor.)
Businesses would lobby for better road infrastructure. Let's say your company distributes stuff to all the corner drug stores around a city. Your delivery trucks need adequate streets to meet their deliveries. Add in the added infrastructure for people not going to city centers (teachers, salesmen, doctors) and the roads were going to be built out anyway.
I think the only way mass transit retains its role in American life is if fuel costs are higher than OTL - coal is much cheaper than gasoline. That requires different geology in Texas, which is by board definition, ASB.
You're not wrong about streets, but that's distinct from highways. The design of 'burbs to be pedestrian-friendly (or mass transit-friendly) is a different issue entirely.
As for how? It would only take a small change in the state (muni?) tax code so rail companies don't pay taxes on the land under their rails. A change so 'burbs pay the full cost of infrastructure, like roads & sewers, would help, too: 'burbs having to pay for streets would have fewer of them, or smaller ones, & better transit access (better still if rail companies could build out more cheaply).
The congestion and smog came about because of low fuel prices and widespread car adoption in the first place.
Actually, there's a good argument for blaming income inequality. It sparks demand for 'burbs (bigger houses for rich leads to desire for bigger houses for everyone else, & they're only affordable in 'burbs, 'cause the taxes are lower...'cause they get a subsidy on infrastructure), & growth of 'burbs increases congestion which increases pollution...
most transit systems were privately owned and seemed to be doing fine in the 1950s, so there wasn't much interest in putting public monies into them.
There was an effort by FDR to trust-bust the power utilities, which owned a lot of transit systems as captive customers. Could that effort be butterflied?
but are more willing to hand over a cent or two at the sales tax box for a public system
As noted, it wouldn't (necessarily) take a subsidy, just a reduction in taxes (of an equivalent amount): that is, cut the tax on land under rails so it equals the #$ being spent on roads. (And, yes, increase taxes on developers. And on the very wealthy, to reduce the
demand for 'burbs to begin with...)