Ubuntu's version numbering system is not confusing at all, it just doesn't follow the standard start with 1 and go up. Ubuntu's version numbering system is the date the version got released, so 4.10 got released in October 2004, and version 14.04 (which gets released in 4 days) means that is is released in April 2014. Not so confusing at all.
Edit: Anyway your point is invalid anyway. The reason the IRS suck at upgrading is because they didn't have the budget to pay for said upgrade. Last I heard, it was free to upgrade the majority of Linux distros. Although there may be many other reasons not to switch to Linux, this is not one of them.