People get into the ring for money when they first start out. When you get to the level of a Jon Jones or Daniel Cormier then it becomes about more than money. Legacy is what it's about as well.
If Jon Jones just wants to make money he can make movies, do endorsements, do boxing, go to the WWE for a match or two, we are talking about one of the most marketable MMA fighters in history. Conor McGregor is showing that you get to a certain level and you're bigger than MMA and Jon Jones had the opportunity to do the same thing Conor McGregor is doing.
I do think some people fight just for the money but how do you get to be as good at it as a Jon Jones without the spiritual or martial artist element? If he really only cares about the money then he is maybe the most naturally talented fighter in history who simply didn't care about martial arts.
Saying everyone does it isn't really good enough. Yeah a lot of people use PEDs but the majority aren't using actual steroids and those who do aren't usually the most naturally talented. Some fighters really need the steroids but Jon Jones isn't one of the fighters who needed it. He had all the natural gifts anyone could ask for, the fighting IQ, the reach, the natural creativity.