In the games industry, one rise is constant: Graphics go up.
With that in mind, keeping a similar income vs. team size vs. dev time equation (adjusting for inflation, of course), something must give.
For many games, it's the length. People don't make twenty-hour epics any more, because twenty hour epics just aren't feasible.
And when they do make these gigantic, open-ended games, something else has to go. In most cases, it's polish, and more particularly, bugtesting. Simply put, all game development is based on linear equations: You put more in, you get more out. The amount going in isn't increasing, so if you want to increase one of the outputs, you have to dial back on another one.
There are plenty of examples of this rule: Blizzard tends to put in time and budget in unlimited quantities, and the games that come out are just about as close to the optimal output as possible. Activision puts full budget into its Call of Duty games, but limits the time. The Call of Duty franchise copes by cutting game length.
2K, however, really doesn't have any excuse with Civ V. Firaxis makes hit games. They have plenty of budget, and plenty of time. They even have prior code that could have been used to fix some of the problems. (Multiplayer especially) They were lazy. That's the only conclusion I can draw.
Here, let's formulize it:
Input=Content Budget+Crew*Time
Output=graphics+content+sound+polish
Output<=Input
Thus:
Graphics+Content+Sound+Polish<=Content Budget+Crew*Time
That is all.
