Because I play other games from other developers that are able to add orders of magnitude more content in a single years than FD has added in the 3 years it claims it spent on this.Really? How do you know this?
I say this because if you just step back and think about whats new:
A new "2 legged" SRV.
A few new assets, rooms, buildings and guns.
Some new UI and menu's.
And (what I openly acknowledge would be a lot of work) the AI for 2 legged NPC's.
an iterative update on the Planet tech.
Keep in mind the whole base game took less time than this update. And the same studio also put out 3 whole games based on the same engine in the same 3 years we're talking about. I don't begrudge them working on other projects, I'm just pointing out that just because it's been 3 years since the last game update that this update is the result of 3 years of work.