Which is funny because these things were a smoke screen from day 1. Google is a past master at doing things for themselves, but throwing in a token benefit for everybody else so they look like the good guys.
Summer of Code was primarily a recruiting tool for Google, not a contribution to open source. They spent 0.06% of profit on Summer of Code, and in exchange got access to some great developers and got a mostly-unpaid trial period to evaluate them. That's a HR recruiting gold mine.
Despite their entire operation running on Linux, most years they contributed so little back to the kernel that they didn't even show up on most rankings -- and adjusted for corp size they were barely a footnote. It's only recently that they have started to contribute anything substantial to Linux. One of their largest contribution to Linux is cloning all the GPL code into BSD code so it can be sold for profit.
Sure Google has done a few good things for Open Source, but far far less than one should expect.