1) They bought Android - they didn't build it in-house.
2) They bought Double Click - they didn't build it in-house
3) They bought YouTube- they didn't build it in-house
4) Third most popular cloud platform is a bit disingenuous; it's like saying Apple Maps is a top mapping platform: sure, you're kind of right, but the gap at the top is fairly wide.
(You might even make the case that the best parts of Chrome weren't built in-house, but taken from open-source contributions via Chromium, but I'm not sure I quite buy that.)
I think the overarching thesis deserves merit: what was the last in-house built product that became a powerhouse with true sticking power, besides Gmail / Google Apps?