Comment by tsimionescu

A good part of why this is is that, with a source-available license, you are almost as much at the mercy of the company developing the software as with proprietary software.

Sure, it's nice that you can read the code, maybe workaround certain bugs, or audit it for security. But, crucially, if the company decides to change their terms ask for much more money, or just refuse to do business with you, or goes out of business, you're in just as bad a situation as if you were buying Oracle software. You will have to replace them with new software, you won't have a choice to continue development or find a new vendor to support it for you.