I would imagine that it might cost a bit more than that. 2000 to 2500 a month sounds a bit low, in my opinion. Granted, I guess it depends on the company and country... but from my experience, a straight programmer can cost more than 2500 a month. Contractors may cost even more.
And then you also need artists, writers, music/sound, marketing, etc.
Testing teams also cost money. Depending on the company, these can be paid quite a bit as well.
I believe Nintendo also has a licensing process/cost that the developer/publisher must go through.
You'll also need to purchase and license development tools. Most industry tools are fairly costly. And of course there are the indirect costs like the office to do the work in and the computers to develop with, etc.
Granted, my thoughts come from a different type of software industry, but I'd assume that there are similar aspects.