And maybe, there should be a separate university degree to reflect that.
A potential solo indie-dev would probably be resourceful enough to go the autodidact path, or cherry-pick their own course plan at a university. Since credentials are less important for a self-employed person, they can get the same value from learning resources.
But I would argue that the primary reason here is because the skills needed to be a successful indie developer have never been formally defined. They are more art than science.
You can't really teach *artistic* talent. There is no one correct way to do art --- or launch a business.
You can learn accounting, finance and marketing --- but it won't teach you the core skills needed to be successful. Lots of *successful* entrepreneurs simply hire these skills as needed.
Picasso didn't have a degree in art and Gates didn't have a degree in indie dev.
Getting a certificate in entrepreneurship without having started your own company from scratch is as useful as having a certificate in painting without having raised a brush.
OTOH, if you do raise a brush, you can just go ahead, paint as much as you want, make mistakes, learn from it. Eventually you will discover a style you like that you can then audit a few university art courses about.
Most teachers/profs/entrepreneurs will even help you for free because although they are in it for the money, they also enjoy it.
Unless your objective was to be an art historian and gain a wide exposure to all and everything art or you want credentials to gain entry to an art studio etc.
Here's one for example: https://www.buffalo.edu/partnerships/about/centers-facilitie...
Some schools like Cornell Tech have masters programs focused on entrepreneurship too.