I have known people with fiercely strong principles and I have known people like Groucho Marx, and a vast majority are like Groucho Marx. For these people, ambition trumps principles. So, if there is a choice between bending their principles to get what they want or to stick to their principles and not get what they want, they consistently choose the former. 

When people justify what they do because "it's their job" or because "everyone else is doing it" or because "I'll be left behind if I don't do it", they are in the Groucho Marx category. On the other hand, if they only do things that are coherent with their principles (which don't change from one day to the other), they are more like the Hindu mythological hero, Ram. 

In my observation (and personal experience), people who stick to their principles are statistically a much happier lot. 

The simple reason is that those who stick to their principles are intrinsically motivated and aren't constantly comparing themselves to others. They are simply focused on doing what they do best and what they enjoy and getting better at it.

And those who don't stick to their principles are extrinsically motivated as they value material possessions and social status, image and perception above what they believe in as good and bad. 

The competition among the extrinsically motivated people for coming out on top is what we popularly refer to as the rat race. 

We see this among product companies as well. There are those that do whatever it takes to get more customers and make more money and maximize their profits and shareholder returns while there are some that strongly adhere to their vision and design principles and always put the customer first, even if it means falling behind a competitor.

If you are one who sticks to her principles, you are in the handful minority. And this makes it hard for more people to be this way. As humans, our default position is to accept and adopt the majority position. This is what helps us survive and fit in and get along with others in our community. 

But the default position is one of misery.