> In my own specialty (industrial organization) unsolved problems which would be of interest to readers here include optimal regulation of platforms and two-sided markets. Theory and empirics are difficult, so regulators are to some extent fumbling in the dark a bit. It is not at all clear how to regulate (for example) Amazon’s offering its own versions of products sold on its marketplace OR what the right tariff Apple should charge for access to the App Store is.

The subject was "unsolved problems in economics", not "unsolved problems in politics". Regulation is a political topic, not an economic one.

That last point might be economic in nature, but only if Apple is the one making the decision, and is free to choose their own price without fear of regulation. Otherwise it's still politics.