It's not black-and-white at all.
There are many reasons.
First of all we're not a very big shop, and administering "dinosaur" CP on the side is no longer viable.
Then, we maybe open a case per year in average. A few years ago I was so frustrated with a case where they didn't understand anything at all. For the price this equipment and support costs that is not acceptable. Which is when I promised our sales guy we wouldn't renew. I tend to keep my promises.
I know support is **bleep** everywhere, but that doesn't mean no actions can be taken. Everyone gets a chance.
Concerning vulnerability issues, people say that CP simply doesn't disclose them. I don't know what reality is, but as long as you stay up-to-date and are not stupid enough to put your management interface on the Internet, you're probably generally safe.
We'll see.
Happy New Year! 😄