neither of those have network effects, they can thrive in oligopoly markets, I think that communication is a winner takes all (ironically why you want it to be an open standard, but such is innovation from startups)
Which cell phone manufacturer has "taken all"?
You seem to be basing your statement on the impossibility of interoperability, which is an odd position to take, at least if you actually think about it.
Phone numbers are universal. It's not like an iPhone user on AT&T can only call other AT&T users[1], or that T-Mobile customers can only call other T-Mobile customers. Skype limits me to reaching out to other Skype users. FaceTime only works with people who have bought into the Apple ecosystem.
[1] Although one might suggest that these iPhone users can, in fact, call no one.
1/ policy makers do not like running a third-party closed-source obfuscated binary with undefined behavior aggressively evading firewalls inside their business or country (in the case of China).
2/ the network effects are not nearly as strong as, for instance, ebay's. i do not care about being able to call random strangers on skype, only about my contacts. the scope of the network effect is to some extent that of a social group, not an entire market.
But more importantly Skype can fix the ux. They cannot fix the freedom issue (and if they somehow manage to do so anyway, great).
So Alice has to install Google talk to call you, skype to call Bob and SIP to talk to Carol
Meanwhile Bob has microsoft phone to talk to ....