[glofish]

Not so obvious that it isn't.

How many hours are spent stuck in traffic? How much loss is that to society.

Perhaps people would start moving closer along the rail lines, now that frees up land from sprawl. Etc. The same rail line could carry goods (fewer trucks on the road). The rail line could be electrified, now pollution will be down and so on.

Billions of dollars is not all that expensive. The US is a rich country. First time realized this when I saw a small town with 30K population easily built a new high school for 150 million USD - compared to that, the "billions" does not sound all that big if it reconfigures the economy at that extent.