The USA's Great Resignation seems to be caused by five factors that I can see so far:

* Covid deaths, some of those people were workers.

* Long Covid, not going to work if you can't.

* increased drug dependency due to pandemic

* workers on the "frontline" noticing they got fired despite being "essential" This is basically the same as "too little work" as in "noticing I'm being screwed over". There's a lot of variations on this, like IT workers realizing their jobs involve an insane amount of work and responsibility which keeps them from what they actually wanted to do with their lives.

* People retiring early, basically because of all of the above (except deaths).

These are the one's I've identified so far, I'd like to hear of any other possible explanations.

The subtitle's better, this is specifically about hourly workers who struggle due to not being assigned enough hours:

"Employers often give people less than 40 weekly hours, leading to resignations and more trouble finding workers"

This isn't the same thing, but one of the reasons I quit my last job was because there was very little "real" work. Sure, there was "work." Basically, lots of pointless meetings and technical busy work: writing documents people rarely looked at, investigating 4 year old bugs that suddenly became important but nobody had a clue about, and, of course, writing more tests and refactoring a dumpster fire to fill the rest of the time.