To add to that, in most cases you can't just move to some country and start looking for a job, even if you have money for the expenses:

You typically need to have a job offer before you can get permission to stay long term. Without that, the most you'll be able to get is probably a short-term tourist visa, which typically does not allow you to work in the country. And most places aren't going to hire somebody who isn't legally allowed to work for them. And if you do find somebody who would employ you (legally), while in the country on a tourist visa, then you'd likely have to leave the country to apply for a work visa.

The kind of job that is eligible for a work visa (and residency) also depends on the "prove you wont be a state burden" rules like the ones you mention, which typically means that you have to have the right qualifications. Most people don't. And you need to stay employed long-term, as you will likely be kicked out of the country if you lose your job and can't find something equivalent within a short period of time.

There are of course exceptions to all this, but those are just that: exceptions