Which is akin to saying that, while doing their Phds and writing papers, they didn't publish all their accrued knowledge in the field. And instead when on to apply that to Google. Obviously, algorithmic intelligence was key for Google, but systems implementations where also very important.

The secrecy they exercised was not only regarding to algorithms, but also to capacity, os design and infrastructure partnerships. They really did a good job at hiding the scale of their operations. Perhaps this secrecy was their biggest advantage, but take into account that they hid much more than algos. And still, the have a huge base of secret IP.