Ah, I suppose what I mean by capitalism is a more pathological optimisation of employees with authority. If you think of a company as something that is optimising for profitability through not only producing something, but by doing everything in their power to stifle competition, by preventing competitors from succeeding by any legal means, then you can look at an employee and their behaviour in a similar matter.
People often have houses to pay off, kids to feed, cars to buy, and they're interested in maintaining their foothold. They might say they buy in to a companies culture but the reality is, if they had to sacrifice themselves for said culture they'd always put their interests first.
So employees with limited power and authority over their little domain, are going to act in their own interests by as you say hiring people like themselves, by creating a culture that matches their values and keeps outsiders at bay, and by ousting anything that threatens the status quo.
It would be really interesting to see how things would work if people were able to separate costs of living and productive activity, but because they're tied up they're going to influence each other.
Why would someone over-quote on a job? Because they want more money so they can buy that thing they want or pay down their house quicker. Why would someone fire someone for not being a 'cultural fit', maybe it's because their behaviour threatens their position in some way. No questions are good questions. If Blackberry could have flipped a switch and prevented the iPhone from ever being made, by god they would have done it. It's the same behaviour and it's prevalent as hell.
So, that's what I mean.
EDIT: It ultimately does come down to money and protecting income streams (i.e. employment) while expending the least amount of energy as required. It's hard work for a manager to look after the needs of a team that has a cultural outlier even if they are ultimately improving business outcomes. It's easier to have people to nod their heads in agreement and show up 9 to 5, produce maybe 10 hours of true productive work a week. It's such an easy think to fake and it happens everywhere.