That’s absolutely untrue. The only reason companies track depreciation as they do is because it allows them to defer taxation. Public works projects are not paid out of current cash.
Strong Towns makes good arguments about certain things and are critical in a reasonable way of how civil engineering organizations rate the need for more civil engineering works. But the budget discussion makes zero sense.
The biggest expenses for county, city, town, village government are: schools, police & fire, Medicaid share in states that do that, and employee retirement and health. A small/midsize city spends 60% of its budget on police.
Capital projects are capitalized with bonds. Governments have the lowest bond expenses due to tax exemptions. Roadwork is not done in a cash basis. It’s bonded for 10-30 years depending on the job.
Yes, the problem is that our cities are already leveraged up to their eyeballs. At some point, the actual humans buying those bonds start becoming skeptical of the city’s ability to pay them back.
LA currently has about a billion dollars of outstanding general obligation bonds (edit: but that does not include all their future liabilities). They're still rated AA, but I presume that is because the credit writing agencies understand how many untapped revenue streams LA has, but again, those will require unpalatable political change. You can’t keep refinancing forever.
Philadelphia, Miami, and Chicago are getting close to junk bond status, and when that happens, the option to refinance starts evaporating very quickly.