I've always called this plausible deniability in corporate culture. "It's not my fault the DB is down. I'm on the phone with Oracle right now, they'll have a fix soon". The OSS solution is much riskier. "I chose this free DB, and now it's broken." In large corporations, the first is much safer for the employee, but much more expensive for the corporation.
As a half-serious idea for a company, I thought of IT insurance. Rather than paying support to Oracle, we will audit your solution and charge premiums based on the riskiness of your setup. In case your OSS DB goes down, the insurance company would pay the downtime.
The company would provide two services. 1) I expect our "plausible deniability" would be cheaper than paying Oracle, and 2) we put a pricetag on the reliability of your setup.