i.e. these high quality but subjective answers are still being created on Quora, but not SO. That strikes me as being a problem for SO.
They are different sites for different purposes and different audiences. Trying to make one site to be everything for all people doesn't work well for any of them.
If SO is for facts, data, and science why do I so often see accepted answers that are wrong. And I'm not even talking about accepted answers that got wrong because the environment changed.
The person who asked the question can only tell if it did supposedly solve their problem. They can't tell if the answer is actually sound advice or if it has subtle problems that another answer solves better.
The accepted answer also gains the top spot, even if other answers have gained more upvotes.