[vklj]

Since Google dropped Jabber server federation, open XMPP are less useful.

And, for voice/video, getting them to work through NAT is a pain, while Skype JustWorks™. Plus, it is a really good solution: I can change my connection from WiFi to cable, and the video recovers within a few seconds.

That said, I'd love it if everyone ditched propietary solutions. But, unless you really care about privacy and freedom, it's a hard choice to make.