Theres all sorts of things that go on behind the scene. We have no idea what is happening at CIG other than what they put out. Think back to the FPS module, [redacted] had it basically finished only to find that none of it worked in engine with the game anymore, we thought we were within weeks of gametime and it turned out to take way longer than anyone ever thought.
For all we know there could have been some sort of enormous problem with the code in the engine or something like that.
Lets put this is perspective. Skyrim took 4 years to make and they already had the engine. SC is infinitely more complex and intricate so who knows how many blocks they will have.
Theyre also being a lot more secretive about SQ42 than SC.
TLDR. You backed a game knowing it was in alpha (or prealpha for me, or concept for original backers) You may not even get a game at all. So the fact that they are constantly putting stuff out and trying to do their best is awesome. They dont like saying or hinting or even thinking aobut release dates cause they have no idea if it will actually be ready or not, and then people go mental about it.