Root causes: The elusiveness of low cost videoconferencing

Over the past 10 years or so I've been trying to make low cost webcam based business video-conferencing work. That's almost as long as I've been trying to unify my family, corporate and personal calendars.

In both cases I've come close to the proverbial brass ring several times, only to see it recede from my gasp. I thought we were close with iChatAV and the firewire iSight webcam, but then Apple discontinued the iSight and lost interest in iChat. [1]

Now we're on another go-round. Over in Gordon's Tech I'm updating a brief state of the art summary. Once again the ring feels close, but I'm not willing to say it's a sure thing.

So what makes low cost business videoconferencing so hard. Haven't we had the basic technology for about 10 years?

Here's my current list. Comments are most welcome:

1. Affordable travel: Current videoconferencing solutions, maybe even teleprescence solutions, are a poor substitute for being there. As long as travel was affordable the market for teleprescence was limited.
2. Unlimited flat rate network access: I hate flat rate access. I want my ISP to want me to burn bits. Flat rate access means Comcast is incented to kill BitTorrent and videoconferencing is collateral damage.
3. Perverse customers: Recreational home p*rn was a major driver of 1990s webcam development software. They want blurry images and attract virus-infested software. Not good for business use.
4. Firewire licensing costs: Unwise Firewire patent holders set licensing costs too high. That meant CPU-sucking wimpy voltage USB took over. Uncompressed 800x600 images at 15 fps uses bandwidth that's no problem for Firwire, but seems not to work so well with USB. In theory USB 2 should have more than enought capacity, but firewire camcorders (Canon's for example) and the firewire iSight delivered much better images. I've long wondered if the USB 2 chipsets of years past were really up to the job, or whether there were issues with older CPUs supporting persistently high volume non-bursty USB transactions. I admit I seem to be alone in this suspicion.
5. Limited uplink speeds and limited reliability of many internet connections: It's not only the historically poor uplink speeds, but many net connections aren't reliable. Video conferencing software is pretty demanding.
6. We need h.264 compression and its variants to make this scale, they're pretty new and demand a lot of CPU (or a dedicated chip).

Any other explanations of why we're still not quite there yet?
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[1] Apple ties their product (ex. iChat) improvements to major OS releases. This doesn't work for me. I think this policy is a strategic blunder.