It is written in the article. A few reasons could be pressure from the publishing magazine, emerging open source implementations of the same idea, and the fact that this is still far from easy to comercialize.
A lot of people will say "Unless you opensource my work and that of my colleagues, I quit".
When faced with all your best people threatening to quit, you might just opensource that work. It turns out you still have an advantage by being ~1 year ahead on applying it to anything, and having all the people who know how it works on your staff.