Rich people do get sent to prison. There are two main legal reasons why their frequency is less.

The burden of proof for white collar crime is much higher. In other words, it takes more prosecutorial resources to take a white collar crime to court.

Rich people can afford better lawyers--which then makes the prosecutional case even more expensive for the tax payer.

If you rob a convenience store, a prison sentence could be in your future.

If you bilk seniors of $5m, you are probably walking free--even if just about everyone knows you did it. But once in while, someone does to prison for this. Usually the sentence is shorter than your average blue-collar crime.

We are still a long ways from a true justice system. But the rich don't exactly have a free ride.