Yes, leaving the country for a long time is another way to lose residency. I was focusing more on expulsion.

In the distant past the US government claimed US Citizens who lived abroad too long lost their citizenship.

The courts said, “no.”

But the US State Department would still refuse to provide consular services.

Some expat US citizens tried to claim this to avoid paying taxes for the U.S. on foreign income.

The courts enthusiastically said “no”.

Isn't it exclusive to the US that you have to pay taxes after having moved abroad, despite living in another country for a long time, having your home address, etc. set there and so forth.

North Korea does it too.

Yes but USA lets you write off taxes you've already paid to other countries, up to ~$150k - $200k of income IIRC (might be wrong here on the details).

You also get other benefits too though. If you ever become desolate or need help getting home, embassies can help or provide a loan. If war breaks out or some natural disaster happens, America will come for you. You get the power of our passport. You can still collect benefits like social security.

Pros and cons.

> If war breaks out or some natural disaster happens, America will come for you.

Sort of. The state department will arrange evac, but if it's a charter on a PJ, you'll be on the hook for it and will have to sign a promissory note for it.

Sending in the military is very rare. You'll have better luck with a private security company, but they aren't cheap.