From: Washington, DC
I would suspect that it has a lot to do with the fact that hexes and squares solve some problems for map based games. The main problem is one of distance. When you think about it very few games both electronic or board based have good mechanisms for displaying and measuring distances...Command ops has built in measuring tools to trace distance. command Ops and games like Harpoon also have features that provide on screen displays of weapon ranges.
I dunno...while I can see the utility of hexes for boardgames, as you suggest for computer games it is would not be difficult to show range in a variety of other ways (range circles, square grid overlays, etc.).
Hexes also help solve another issue - unit facing. In some games that can be relevant. I'd suggest hexes are better at this than squares. Hexes and squares also allow for concepts such as ZOC's by providing a defined area of effect.
While I agree with your point, another oddity is that virtually no operational games deal with unit facing. Again, your point for ZoCs is valid, but hexes would seem to limit as much as they facilitate ZoCs--seems like ZoCs should depend on unit range, mobility, size, etc, while these factors are rarely (never?) used when calculating unit ZoCs.
One interesting issue with having no tiles is "terrain fidelity"--what size are the terrain elements that can be placed on the map? One pixel for individual trees? Square blocks of a set size of various terrain types? Being able to draw terrain freehand of any shape? I forget how Command Ops does it, but IIRC it is the latter approach.