While the use-case seems trivial it's a pretty challenging engineering problem; a lot of people who saw the original AirPower announcement and corresponding patent drawings[1] claimed immediately that it wouldn't be possible or would be unbelievably hard without advances in materials and it looks like those criticisms are bearing fruit.
[1]: http://www.patentlyapple.com/patently-apple/2018/07/apple-re...
Any other solution would seemingly still have the orientation issue.
I nearly never want my Watch and my iPhone on a charger at the same time because I pretty much always have at least one of them with me. And I charge my AirPods case so rarely (I plug it in for a few minutes once a week or so when I think to), it's not really compelling to me that it charges it separately.
Anyway, I'm sure other people differ...
https://www.apple.com/shop/product/HLZ42/belkin-boost-up-spe...
So, although I've never used one myself, clearly these chargers are feasible and the overheating challenges the article lists are solvable. I know the Belkin one looks more simple (1 device instead of 3), but why doesn't Apple enter the market with a similar product? The article doesn't really answer the question for me of why Belkin is creating one but Apple is not.
Edit: Not sure why I'm getting downvoted. This is a genuine question and it's getting a lot of informative responses.