They're all well aware. But companies like paying for things. They don't like legal gray areas about licensing, patents, copyrights. They just want to pay for a license and get indemnification and some kind of assurance they won't get sued or extorted later by some trolls.
A lot of it is also they like having the capability of picking up the phone and getting someone to prioritize / look at an issue they care about. Good luck trying to get an OSS dev to do that for you if you're in an industry that dev doesn't like (i.e. military development).
With a negotiated support contract you have assurances that developers are willing to deal with you, that they're probably not going to just up and vanish, and that they've at least agreed to at least consider issues that you run into.
Almost all of them say that their tickets are attended to within hours of filing, and Oracle offer support in over 20 languages so they must have a pretty big team to be able to do that.
Yes, the Oracle support is probably the best among the large software distributors.
And no, it won't solve some problem you detected. It will only help you if it was already solved by development.
Anyway, time to attend to a ticket is a useless metric. I bet Microsoft fares better on this than Oracle, but their support is absolutely counterproductive. (What I mean literally, you will get your problem solved faster if you don't try to deal with them.)