I'm sure Linux would be much more popular but for the ongoing "geekspeak" problem mentioned in the OP.
Therein lies the problem.
Linux is a great big open source "community" project..... you are reliant on the community to code it, and reliant on the community to support it.
Given that the primary application of Linux is in a server environment, 80% of the linux community are either professional or amateur sysadmins, perfectly happy with the command line because they administer machines without displays connected.
The 20% of people who use the various GUIs implemented on top of Linux are then left with a lacklustre support infrastructure.
Add onto that the fact that different people use different Linux distributions that have differences ranging from minor to extreme, limits your support offerings even more.
Add onto that the need to differentiate between the GUI and the programs that run on it, and the differences in quality and pace of development on those.
That is, in an essence, why desktop adoption of Linux variants is not widespread and is unlikely to be so for a while yet. At least with Apple and Microsoft you know what you're getting.... application developers get an OS with clearly defined APIs etc., and the users get to reap the benefit of a more formal design and development process.