>Passport card can be revoked over fairly small amounts of late child support

This is clearly ridiculous and not in any way connected to the reason passports exist. It's just purely bureaucratic tyranny.

Even the stated goal of "preventing people from running away to other countries" doesn't work, because the USA doesn't have border service check the passport _on leaving_ the country.

There is no check on leaving, and our neighbor Mexico not only usually doesn't check, it's constitution* explicitly prohibits requiring passports for entry. And when you return US has to take you back, if citizen, passport or not. So you can easily go to and from Mexico without passport.

Virtually every time I go to Mexico, I'm one of very small % with passport going either direction.

* This is debated and some questionable court cases that actually protected rights of indigenous Mexicans to travel are cited as reasons why this constitutional provision isn't in effect (even though the case was clearly written to protect indigenous rather than justify overthrowing the constitution), but go to a land border with Mexico and 9 of 10 times I find they follow the constitution and don't check passport.