Why do Japanese developers take so long to make a single game?

[Barozi]

Many Western dev teams have more employees (EA Canada, Rockstar North, Ubisoft Montreal, DICE, Eidos Montreal) and thus can pump out games more frequently.

But there are also a few dev teams that need 3+ years to make a game, like Bethesda Softworks or Irrational Games.

As for CoD, each of their 3 dev teams is making one game, so the cycle has actually been increased from 2 to 3 years per game.