As an example, UW Madison which has a fairly large and profitable athletics program generated 12 million in profit last year. They aren't the largest athletics program in the country, but it is bigger than many. Sits around the middle.
The patents and IP owned by the university provided $134 million in grants and support. Again, the school has a large STEM component, but it isn't a top tier university. Again, sits around the middle. The organization providing this funding manages its investments carefully and intends to provide this level of funding year after year.
Research departments generated more revenue and the funding is likely more reliable.
I think a lot of that stuff is people buying items in bulk off alibaba, rebranding it, and listing. Most of it is crap, but that's how stuff like it can be so cheaply produced, it's one or two factories producing at scale.