Is Linux market growth stagnated (at least)?

This article is meant to provide some food for thought, concerning the (probable) surcease of Linux growth. I am not saying I know something for sure here, I am just having this feeling that 2011 was the best year for the Linux desktop and will try to share a maybe somewhat premature picture, using multiple information sources. Note that when referring to Linux I mean GNU/Linux distributions and not the kernel alone so Android will be considered something different here.