The big difference here is that states can simply buy access to, e.g., a Cisco Nexus and attack it from inside and out until they find a vulnerability in NX-OS, let's say, a malformed CLI-via-HTTP call.

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.