Are you putting us on? The work load is monumental. Somebody has to design the whole game before coding starts, which is a huge job in and of itself. I haven't seen long breaks between the games where this would occur. Then there is the debugging, which you seem to be doing on the fly. Somebody writes all the dialog, and that takes some creativity (translation: time to think). Also, people who have strong visual abilities, which are needed for the graphics development, usually don't have the type of brains which program in free flow. That's a speed issue.
Not trying to be offensive, but I think I figured you out correctly. Even if you have no life otherwise, there are only about a maximum of 360 work hours per month [time between releases]. It's just arithmetic, supposing additionally you really love what you do.
Then there is burnout. You have ostensibly been doing this for years now. Yes, efficiency comes with experience but so does burnout. I don't remember any vacation time???