The majority of the team is actually said to be working on the "solo" project which is Squadron 42. So they have an excuse for the sluggish development pace. Funny thing is, there hasn't been a single footage of SQ42 in 5 years, and you can't even buy the game anymore. There's a roadmap that says that the game is nearly done, but well, they seem to say this all the time.
I would say it can take an infinite amount of time, if you have bad management, scope creep (or no defined scope at all), high turnover, obsoleted core technologies, and if people give you money even if you don't do anything anyways
