What about this isn't just the network effect problem?
Skype wins on network effect. (My utterly nontechnical mother got broadband *just* to Skype to her grandchildren. "Video phone" = "Skype". [1])
Ubuntu included Ekiga in the default install for ages. It works perfectly well. They eventually took it out because pretty much no-one used it.
I submit that the problem is not the software itself - it's gaining network effect for the software, to overcome the proprietary incumbent.
- d.
[1] yes, this is bad, but I'm describing the ground first.