Cisco's priorities are more directly profits. Google's are often more security related, though they can profit from being more secure.
Whereas, what software does a Google switch even run? What's the architecture, the APIs? You basically need someone inside Google, or for one of these things to fall off a truck. Way more involved and expensive than the 10k you might spend on a Nexus to throw it your lab and set your hackers on it.
https://cloud.google.com/security/whitepaper
(work at G)
cisco has an incentive to not look foolish, but they don't particularly care about any small or mid-size accounts. Your people have an incentive to care about your security and functionality. Weigh up the advantages and disadvantages and make your choice appropriately.
Maybe not smart to roll your own everything, but a few of them sure.
Note the authors.
I don't doubt that Google's trying to come up with new, novel cryptographic methods as well, but those take a long time to develop, test, and get reviewed. RSA didn't show up over-night and SHA3 has taken some time to get ready for production.
What makes Amazon unique is that they built their own networking chips