Further, just because there is a market doesn't mean a business should go out and grab it. I think one of the reasons HTC is apparently doing well at the moment is they have remained focused primarily on one thing; flying. All aspects of play are designed to enhance flying, therefore the main thrust of development is towards delivering a quality flying experience. As the market evolves we have noted pushes in other directions as well, but always the primary concern is flying.
HTC has already said there would be submarines and grunts in the next year; this should not be construed to mean they will be fully fleshed out as in a stand-alone fps or sub simulation. It does add a new dimension to gameplay nonetheless, and gives the pilots something else to think about.
This is not WWIIO; ironically it may wind up succeeding where the other appears to be failing, why? Because we all know walking in what is the primary focus of the game. We understand how the other pieces fit into the picture, and hopefully won't try to micromanage every aspect (too much anyway) of the fps and sub aspects. WWIIO touted a complete implementation of all aspects of the game, and sadly this appears to be beyond their grasp.
This in my opinion is why it is a waste of time to compare AH to WWIIO.