I think Elite: Dangerous also had a three year headstart on development, but don't you also have to pay like $150 to get access now? But I agree to a certain point, the flight controls are very touchy with a mouse and keyboard. I wish they would speed up on releasing things, I understand that they have no publisher to make them put things out, but I'm also impatient.
They were working on the game engine for a number of years before Star Citizen was around. Not sure about when the actual development of the game started, but having a custom engine designed specifically for your game is a huge deal over SC's just using the Cry Engine and attempting to adapt it to do what they want. Of course, if Star Citizen did that then we wouldn't see the game until sometime around 2020.
I would continue to expect delays in the future, as that's just what happens in programming. I don't know that they'll be quite as lengthy as Arena Commander, though. Part of the reason for that delay was because they were originally going to release it with just basic Cry Engine netcode powering it and they decided to skip that step and just go straight to building their own.
Still, I would be extremely surprised if they hit their 2014 release date. I would more be thinking that we'll see the beta for the persistent universe in Q1/Q2 of 2015 and the full release in Q3/Q4, which gives me plenty of time to check out Elite: Dangerous once I don't have to pay the ridiculous price for a beta slot =P