Why can't I receive all local HD stations?

[Ghoulish Delight]

Bloody hell, what ever happened to standardization?!

Okay, so I've just learned that some HD stations (namely, the ones that are broadcasting over the air anyway) can be available over a standard digital cable line without need of either a cable box or an HD package from the cable company as long as the TV has a QAM tuner, which ours does. So I went ahead and tried it and voila, HD stations, no antenna needed! Hooray!

But we're not getting all the stations I might have expected. We get CBS, NBC, KTLA, KCET, and KOCE. What happened to ABC, KCAL, and Fox? I get them via the antenna, why not through cable? The TV auto-scan doesn't pick up the HD versions of those stations, and it won't manually tune to them (11.1, or 9.1 or whatever). Is there something I can adjust to get them, or does that mean that Time Warner, for whatever reason is refusing to put those stations unencrypted on the line, forcing me to pay for HD service to get them? Based on their package listings, there doesn't seem to be any difference between those and the ones I'm receiving, but I don't think their package listings reflect these "clear QAM" signals. It's probably something they don't want to advertise and would rather I pay for HD service.

I've sent the question to Time Warner. God knows if they'll ever respond, or if it will be anything more than, "Our HD offerings over basic digital service are very limited, can we interest you in an HD package with set top box?"

And the first person who suggests I switch to DirectTV or Dish or any other service will suffer. Miserably. Woe to the 2nd person...