I’m going to provide a different reply than the others.

Yes, I would consider 8 years a long time to make a game like Helldivers 2.

But all that means is that a studio in a good position to make that type of game would likely be able to do it in a much shorter amount of time.

In this case, we have a studio that was, in hindsight, too small and trying to be too ambitious in the game they were trying to make. So, trying to grow a studio at the same time you are trying to build an overly ambitious piece of software is going to have multiplying affects on how long said project will take.