Building computer networks and artificial intelligence are pretty much Google's core competencies. Most if not all other companies would struggle to fund and develop this project.

First of all, the system is in total very expensive: You don't get any coverage with just a few baloons, you probably need hundreds to make any of them stay connected to the rest of the internet most of the time.

Second, this system is extremely stochastic and complex. The winds are mildly predictable, so they will have to optimize the balloon paths to cover their userbase.

This is a very exciting problem once you think about it...