There is no reason for so many people to waste so much energy travelling such large distances every day. Commuting in cars from bedroom communities to CBDs is not somehow essential to our economy. It is one of many ways to organize land-use and commuting patterns. It just so happens to be wildly inefficient. When the car was new and the externalities weren't well understood it seemed perfectly reasonable to encourage these commuting patterns. Doctors used to advocate smoking cigarettes. We know better now and our public policies should reflect that.
It is not essential to our economy. It is, however, far faster, more flexible, and more comfortable than taking transit, biking or walking unless you are a devotee of one of those modes. I walk and take the T to work daily. If I am traveling from there to my parents' house, a trip entirely possible on MBTA trains, I will spend 90 minutes crushed in a smelly mass of people with no room to shift my feet, and G-d help me when I have a bag of any kind. In a car, the trip takes, in the worst traffic, half that time, and I get my own space with my own music and my own climate control.
What do I gain for using this far worse mode of transportation known as transit? I can live in Cambridge without having to worry about parking, and I save heaps and heaps of money. a heavily subsidized transit pass costs me (once my company pays for most of it) ten bucks a month. That's my transportation cost. Without my company subsidy, it would be seventy.
A modest car would cost me somewhere in the neighborhood of $500 per month in payments, insurance, gas, parking and tolls. That doesn't count the income, property and sales tax money I'm paying in to maintain infrastructure.
A car is a far more luxurious mode of transportation, for which I would be (if I owned one) paying luxuriously. I would also paying far more of the cost of my transportation than I am, since I would be paying my vehicle cost and there's no way in hell it costs the MBTA $60 per month to move me.
If you want to talk about "paying what it costs," fine. Then advocate that T fares be $8 each way for those able to pay. I get that we disagree on this, but the Government simply can and should not value certain lifestyle choices above others. If your argument is that people should pay to move about, great. I support tolls for that reason. Just be consistent and make everyone pay so the system can function, and don't keep insisting that the sub-population actually paying their costs should keep getting hit up for money just because "their way of life is evil."
This was one of the key enablers for the system to become as unbalanced and irrational as it is. The commuters are really free-riders on a military investment. The national security aspect justified spreading out the costs rather than making individual motorists pay for using the system. I'm not suggesting this was some devious conspiracy. It made sense at the time.
You're conflating two things which have nothing to do with each other. Commuters may be riding on a military investment, but that in no way means that they are on the hook to pay off that investment. Now, maintaining that investment today should be on the users. Again, I support tolling the interstates for that reason.
We, as a society, need to be more rational and realistic with energy use regardless of the source. Even in a carbon-free energy economy (which is impossible to imagine in my lifetime) human beings need to figure out how to use less energy in our daily lives. Economic growth is tightly coupled with energy consumption growth. We want economic activity to grow exponentially in perpetuity, but if energy consumption (regardless of source) grows exponentially we will literally be heating the planet due to basic thermodynamics.
Heat engines and electric motors have theoretical limits on their efficiency. At some point we will need to choose to travel smaller distances less often.
Economizing one's life and habits a good thing, in all respects. People will, by virtue of existing in a modern society, use energy. The balance you have to draw is how much modernity and comfort you're willing to demand that people sacrifice for less energy consumption. Since you present no data with which to analyze that and I can't take the time to find any, I'll have to leave it at that.