Are there any books on the history of economic, marketing and design choices of LEGO and the company?
Yes, there actually is a book that discusses just this subject AND it's primarily focused on the post-2000 years:

Brick by Brick: How LEGO Rewrote the Rules of Innovation and Conquered the Global Toy Industry by David Robertson.

I highly recommend this book - while professing to be a business book, it gives huge insight into the companies design-reasoning and history. 

Amazon Link here.