The commutes are just the other side of the same coin: The way the US treats it's work/life balance has had deeper consequences. If you aren't expected to leave the kids to school and also have dinner with them at 5pm, then you might just as well work a long day. And since you are working late anyway, you could just as well have a longer commute. On a weekday, work is expected to be a full day. Not just half the day. The 2yo will be asleep when you come home anyway. So imho the sprawling city is born from not just the car culture, also the work/life balance culture.
If you are supposed to leave kids at 8 and pick them up at 4 then obviously a 1h commute isn't really doable. Public transit and compact cities follow naturally from that.
I have to wonder, which is more efficient/beneficial for the society, two people both working 7.5 hour days, or one person working 10-12 hours and another staying at home.
I think it depends. In the long run the trap that must be avoided is when women (usually women) leave the workforce after having children since "one parent stays at home" often means "mothers stay at home", after which they have a hard time reentering it (or have to re-qualify/take other jobs etc, which is a huge waste).
If the burden of looking after children is split more evenly between mother and father (say 1 year at a time as long as necessary) and both parents keep their careers afterwards, the difference is smaller. The question is what the state can do to encourage this kind of equality and prevent women from leaving the workforce. The view in progressive economies tends to be that it's long parental leaves, where there is a large part earmarked for the father.
Edit: I should add that the US actually has a pretty decent labour force participation for women. The view that women in the US often end up "homemakers" after having children seems to be pretty exaggerated.
There are countries (Italy and Turkey stand out) where the situation is much worse, to the point where it probably makes a significant dent in the GDP/Capita.
If you are supposed to leave kids at 8 and pick them up at 4 then obviously a 1h commute isn't really doable. Public transit and compact cities follow naturally from that.