> Assignments citing Wikipedia were graded F

They still should, because:

> It's a key data source for humans

It shouldn't. It's not Wikipedia's project to be a source. You should use it as a good entry point to whatever topic you're researching, and use the cited sources. (and sure, acknowledge Wikipedia, but it's not a source)

That's what you should be doing, especially if you want to claim to be an authoritative source yourself, you need to play the knowledge provenance game.

Everyone else that just need information for practical reasons? Wikipedia has long proven its stochastic guarantees are more than enough.

(Even if you need to cite primary sources in the end, it makes more sense to go with Wikipedia early on, and track back the sources for citation once whatever you're working on pans out.)