Boston/Cambridge? Expensive. But 45 mins or so out? Far less so. And you're closer to where most of the jobs are anyway. The urban cores may be a lifestyle choice. But it's a luxury choice in many cases. Not a place that someone actually has to live if they want to work.
Is this a case where a small increase in supply would decrease the price significantly? I doubt it.
So, is there some reason we (as a nation) need to double population density of our largest cities? With the huge advances we are likely to see in autonomous zero-emission delivery infrastructure and remote communication over the next 20 years, not to mention the increasing likelihood of natural disasters and WMDs hitting these cities, I really don't see the point of pushing for so much urban growth.
Apparently my property taxes can't even cover the cost of pavement and water mains, and yet we just built a new school, and are in the process of planning a $20 million library.
[1] - https://www.strongtowns.org/journal/2017/1/9/the-real-reason...
From the link: "If they operated on accrual accounting -- where you account for your long term liabilities -- instead of a cash basis -- where you don't -- they would have been bankrupt decades ago"
The PF analogy to what you're saying is "yeah I'm dipping into savings to make mortgage payments and need to replace my roof next year and repair a major crack in the foundation. But they let me open a credit card and get a loan for a car, so what's the problem?"
That's just, like, your opinion, man. I prefer living in denser environments.