Skype is "free software." I take it you mean /open source/ software?
Frankly it is because there is NO open source software in the VoIP/IM/etc space that is worth five minutes of your time, let alone full usage of.
Every time this point comes up the OSS apologists start naming some convoluted solution involving stringing five different software packages (and a SIP provider!) together to get even then a barely workable solution.
In general this is one of the least competitive sectors that exists. Right now we have Google+ and Skype, and even Google+ barely implements 1/8th of Skype's feature set.
The term "open source" was coined to sell free software to business/the masses, ignoring the core of RMS' philosophy (with which not everyone agreed). The terms are different.
Frankly it is because there is NO open source software in the VoIP/IM/etc space that is worth five minutes of your time, let alone full usage of.
Every time this point comes up the OSS apologists start naming some convoluted solution involving stringing five different software packages (and a SIP provider!) together to get even then a barely workable solution.
In general this is one of the least competitive sectors that exists. Right now we have Google+ and Skype, and even Google+ barely implements 1/8th of Skype's feature set.