No. OS-X, Windows, iPhone and Android are sufficiently different that we can tell the Skype developers are putting a decent amount of effort into cross-platform compatibility.
That there is a Linux client shows they are also trying to do that with Linux.
Could they put more effort in and get a polished shiny Linux client? Maybe. Is it Skype's fault that Linux is bad enough to need this while at the same time not good enough to get a large enough userbase to make this worthwhile? Again, no.
No. OS-X, Windows, iPhone and Android are sufficiently different that we can tell the Skype developers are putting a decent amount of effort into cross-platform compatibility.
That there is a Linux client shows they are also trying to do that with Linux.
Could they put more effort in and get a polished shiny Linux client? Maybe. Is it Skype's fault that Linux is bad enough to need this while at the same time not good enough to get a large enough userbase to make this worthwhile? Again, no.