What should be an owner operator net income per year?

Back in 2010, I was at that hospital in a waiting room, somewhat distressed when my wife was undergoing a surgery. I grabbed a Time magazine from a coffee table, there was an article that somewhat stuck in my memory until today.

Do We Need $75,000 a Year to Be Happy?

It states that people are the happiest when their personal income is $75 000 per year. The way the research was done was that the respondents were asked about the life satisfaction and also asked about their income. At the time, as a driver, I was making $62-65K and indeed I was not satisfied - not enough for me. I knew quite a few owner operators who were saying to make close to 90-100K and indeed their demeanor appeared quite assuring that they were living happier lives. Not only that they could afford more things, but more importantly, some of them were expanding - buying more trucks and hiring people - that's quite a different level of self esteem to become someone that other breadwinners depend on you. It is not even all about money at that point.
I also noticed that many company drivers, earning higher salaries, do not have that drive towards truck ownership. As matter of fact, they often scorn at the idea as it is nothing but life complication. Walmart drivers, for example, who I was able to chat with, were quite happy with their jobs (80 - 100K - I guess).
I quite agree with those who said earlier that it brings quite a substantial freedom. I honestly don't know, if I could trade it for higher earnings, say even by 20K but in exchange to have a boss to answer to. Anyway, It looks as if we take home $75k and more we're doing OK. The more the better. No one wants to make less. I personally, think that 100K is a good benchmark to make a good impression among us. Someone might have a working spouse, who can add 50K or more... then we're talking 150K -200 per household - is it not middle class? I don't really care, but with that income you can hope for a happy retirement. The only thing is, make sure this job does not kill you before then. Many of us are not supposed to live past 60...the statistics say.