Wireless charging is solvable but the sales pitch for AirPower was actually pretty fundamentally different; AirPower would allow for up to three devices without "sweet spots". Traditional wireless chargers require the device to be in a specific location and at a specific orientation (which is why many mats and Qi-enabled devices have magnets, to enforce this).

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...