If the system can successfully masquerade as an older Skype version it stands a chance. That is unless Skype has a baked-in not yet understood mechanism for pushing protocol changes to its clients. Skype would have to find discerning features, implement it on their servers and possibly even push it to their client updates. Whenever such discerning features were found it's a simple matter of arms race, i.e. a difficult but fair chance. Alternatively Skype can start blocking older versions which is rather unlikely.
Concerning the open and better issue; There definitely are open alternatives. None of them have quite the firewall-defying capabilities of Skype. Nor the user base for that matter. Building any kind of social network is fraught with chicken&egg problems and those first to reach mass have it made. Just check how one of the richest and most powerful technology companies Google is struggling to get a foot in Facebook's market.