Because a billionaire isn’t “just as guilty” in an exploitative system. They are more guilty because they benefit more and they have more power due to their capital. If you can’t see that, then I guess we won’t ever agree.
Do you have a job? If so, you should know how hard it is to earn money. The level of effort required to even get minimum wage is usually astounding. And maybe you went to school and learned to do more skilled jobs, so you don’t have to work as hard as a minimum wage laborer. Maybe you can justify it as being smarter or more skilled and that’s fine. But do you think someone that “earned” a billion dollars actually worked ten thousand times harder than someone who earns 100k. Or a thousand times harder than someone that earned a million dollars. Or are that much smarter or more skilled?
In your original example, you talk about how and individual could make a game that could get 300 million in sales while ignoring that vast amount of effort it realistically takes to do so. Way more effort than a single individual person can do. Getting to those kinds of sales would take the effort of many people, so if a single person benefits more than the others involved in that effort, then they did so by exploitation of their labor.