You are focusing too much on legal definitions.
The intuitive difference is mostly between the many and the few. Between the ordinary people and the elite. If your money comes from many small streams, it looks likely that many people have independently determined that what you are doing is valuable. If there are a few large streams, the situation is less clear. Maybe your contributions are genuinely valuable, or maybe someone is picking favorites or choosing winners in advance. From that perspective, capital is a poison that permanently puts the reasons of your success in question.
Or maybe your industry just has very few, but very large, clients. Like spaceflight (SpaceX).
If anything, I remember when the U.S. Senate Appropriations Committee was picking favourites - and that favourite was ULA. Elon gave them hell.
https://m.youtube.com/watch?v=upnx_DD9zSQ
On the other hand, SpaceX has a handful of very large clients, and around 12 million small clients, which probably provide a less clumpy income.