I always told people that the difference between the US and Belgium is that you "live to work" in the former and "work to live" in the latter.
Belgian labor laws are much more enforced than they are in the US. The unions in Belgium have a lot of sway in big companies and employers tend to respond positively to work-life balance.
In the US, there's the expectation that if you're hired for a role, you should be able to onboard as quickly as possible. There's no 6 month trial period or even the concept of an indefinite contract (CDI in French, I forgot the acronym in Dutch) (EDIT: in the private sector).
Likewise, an American employer can get rid of an employee (and likewise hire one) in less time and with less cost than a Belgian one. That flexibility drives a lot of the business decisions in a way that would never translate in Belgium (or much of Western Europe, for that matter).
On the other hand, if you're in a situation where your employer goes over the line (like the person at the top of the thread describes), you can generally just walk away from the job. There's no 6-week notice.
There's for sure a lot more to it, but that's mainly where I see the difference between the two countries.
I think this is exactly what was meant by op. Why is there so much complaining? If it sucks, just walk away. It should even be easier in the US than in Western Europe.
Realistically, in the US so much of your financial health is tied to your employer that the advice to "just walk away" is only safe if you're already financially secure and don't need a job. Aside from the steady paycheck you're likely to lose: medical insurance, dental insurance, tax free retirement savings, and the unvested portion of your stock/retirement savings at a minimum. If you're in a position that tends to pay a yearly or even quarterly bonus, you're walking away from that too.
You're also going to lose a number of smaller items that can be expensive. Does your employer pay for the tools you use to be productive? How much does a JetBrains subscription cost these days? Or an MSDN license? How about all those AWS instances you use for sharpening your skills? Time to start ponying up or doing without.
This doesn't even count the other perks and benefits that companies are throwing at employees for highly competitive positions. Enjoying that free gym membership? Not anymore. How about the free snacks and lunches? That's another expense you can add back in now that you don't have any income. Free coffee in the break room? Time to find out just how cheap you're willing to get with your daily dose of caffeine.
Now factor in that for many being unemployed for extended periods of time can lead to severe depression and a lack of self-worth.
Don't forget to also factor in that 22% of divorces in the US are because of "money issues" which can usually be translated to "lack of money".
Taking the above into account I would likely put up with some pretty awful employment practices while looking for a new job rather than just walking away.
As well as your literal health, since your health insurance is so often tied to your employer. Extended unemployment could literally be fatal. It's a bit easier to get health insurance without a job than it used to be, but there's still a lot of overhead and hassle.
Likewise, if you quit voluntarily, you aren't entitled to unemployment right away.
But I agree, you'd most likely want to have your next job lined up before putting in your notice.
If you are a decent engineer in any tech hub like Bay Area or Seattle, you can absolutely walk out of your job and get a ton of interviews scheduled by the end of the week and have at least a few offers by the end of the following one.
And hiring is just as costly and difficult for employers as you described. A lot of times, we have to go through so many candidates just to fill one position, and it isn't just for something ultra-specialized like an AI researcher or a kernel dev, we are talking your run-off-the-mill solid software generalist. The estimates easily go to above 30 candidates interviewed per position filled.
If I quit, I can get a job within a month which gives the same or better pay.
From the company view, they need to spend several months trying to find a new employee, and then give full pay while that person is still learning the codebase, and other employees wast time getting him/her up to speed. It takes another few months before this person is 100% productive.
So as an employer, you are basically pulling on the shorter end of the string.
So my question: why is it so much different in the US?