That’s an ideology, not how things actually work for most people. It is not about work ethic, character, or force of will. There is a massive imbalance of power between employer and employee and people can’t always just walk away from toxic workplaces.
If you’ve always had that privilege, then that’s great for you. Just try to understand that it’s not the same for everyone. If you think it is, or that your success/contentment is some kind of proof that your experience is the norm, here’s something to read:
https://en.m.wikipedia.org/wiki/Survivorship_bias