That's not the case everywhere though, which is the observation that TFA and the parent were starting from. Obviously if you do make more it's ok.
>And if my company has layoffs I'm one of the last who would be let go.
You'd be surprised how many people thought that and got the short end of the stick.
It's a delusion that helps people sleep at night...
The times I've been at a company where shitty politics supersede reasonable practices, I've left. And having a resume with greater achievements makes this easier than a resume with fewer.
The famous example Taleb uses in his book is the Thanksgiving turkey.
"Consider a turkey that is fed every day," Taleb writes. "Every single feeding will firm up the bird's belief that it is the general rule of life to be fed every day by friendly members of the human race 'looking out for its best interests,' as a politician would say.
"On the afternoon of the Wednesday before Thanksgiving, something unexpected will happen to the turkey. It will incur a revision of belief."
http://www.businessinsider.com/nassim-talebs-black-swan-than...
However the inverse isn't true; your employer doesn't pay you as much as they possibly can for 40 hours work. They pay just enough.
So why not work just enough? It's meant to be a balanced exchange.