I asked the OP's question before and got a similar array of unsatisfying answers: (1) track sprinters stress the wheels and so they must be strong (2) lack of R&D in the track sector (3) aero is more important.

I still don't see what's stopping Easton, for example, from taking one of their Circuit real wheels (955g, 28 spokes, 28mm rimm) and swapping the hub to a fixed-gear hub (which would be lighter because there is no freewheel). The front wheel can be used for track or street riding without modifications (695g), and the result is less than 1650g for a track wheelset.

Even if track riders don't take to it (not aero enough, flexes too much), it would be great for single speeds and commuter fixed gears which, as we know, are markets not too be ignored today.