The biggest hurdle by far is that you need to compile the software you want to use from source more often that is acceptable for the average user. There is also a serious lack of proper hardware driver support.
Linux is way too fragmented and trying to get up and running with basic apps requires way too much technical skill.
I really do hope that SteamOS will finally solve these problems by having the backing of a foundation (company) that has years of UX experience (with multiple failures and successes under their belt) that targets a wide range of audiences. This should give hardware manufacturers confidence that developing drivers for that OS will not be a waste of time.
I’ve already been down voted and commented on. No need to start being a snarky asshole. If there is one thing that hasn’t changed since the 90s it is how obnoxious and pretentious Linux users are.