You ask the wrong questions.
Being nice is the wrong thing.
The world is full of people, good people, bad people, nice people, not-so-nice others.
It is not a coincidence that the cutthroat sociopath-like people end up on top. Your moral high ground is their advantage. They'll stab you in the back at the most convenient opportunity.
To get ahead, you can rely on the kindness of others, with some luck...or you can abuse the kindness of others.
In a just world, they wouldn't exist. We'd all share and be happy. There would be no war because there's nothing to be gained from war. Businesses wouldn't be anti-consumer despite relying on them because there's nothing to be gained from it.
But there's always something to gain, and always someone bad enough to abuse the hell out of everyone to get their way.
In the end, it depends on how you look at things. I'm of the opinion that a disreputable, dishonest asshat can always be depended on to be a disreputable, dishonest asshat. ...And that we should base our rules, laws, and economics around minimizing the worst they'd aspire to, while maximizing the gain from everything else they get up to.