The author appears to think that optimizing for tax revenue is one of the main goals of publicly funded transportation infrastructure (a category which includes roads, sidewalks, subways, etc.) or is at least not a terrible idea.
I cannot even begin to convey how much I disagree.
The purpose of public funded transportation infrastructure is to make transportation cheap (in terms of time, money, frustration or any other metric, they are all interchangeable) to the point where anyone can use it. In an ideal world physical distance would be negligible part of any decision. Travel would be as inconsequential as getting water from a faucet. Obviously this is little more than a fantasy.
Making cities walk-able at the expense of some longer range form of transit is not something I endorse in any way shape or form. Making longer range transportation more expensive (time and money are basically the same thing at this level) creates a negative incentive for people to move about beyond a the limited distance of cheap alternatives (i.e. walking). While that may be a benefit to the wealthy it creates is a detriment to the poor. For example, you're stuck paying too much for bad selection at the local grocery store because you can't afford the level of mass transit pass or a car that would let you get to the better grocery store in a reasonable time (or maybe the increased demand for buses and rail degrades their quality substantially).
To hear the author toss in the tax argument annoys me. Transportation isn't free. It costs money and time. It's basically a tax on physical distance. There's no such thing as good roads in a city. They're busy and slow during basically all the hours which people want to use them. People don't pay for a car or rail pass because they want to but because the benefits of increased freedom of movement outweigh the costs. The costs aren't cheap. If increased business/commerce and tax revenue is your argument for reducing the capacity of people to get in/out of your city then you should be asking yourself how the heck you got to a the point where people would rather put up with driving than live/work/spend money in your city.