You’re talking about Fortune 50 companies here. I don't think Google is going to be messing around spying on them in direct violation of the no-doubt sophisticated contract that will be signed between them.
That was not with Google's consent and it was quickly shut down by enabling encryption between nodes in Google's internal networks. Your average company is far more likely to be susceptible to state actors than Google is.
According to the documents leaked by Edward Snowden, that espionage was sniffed in-transit in plaintext across the Internet's trunk and filtered against XKEYSCORE queries for eventual collection. Google's surprise came from the expectation that cross-datacenter traffic was sent over direct circuits and not susceptible to interception.
It was totally unrelated to PRISM, which was more like a voluntary law enforcement access portal that autoapproved every request. The participating companies since made public statements saying they no longer operate the portal, thereby forcing intelligence agencies to use National Security Letters instead. That's certainly closer to the intent of the laws passed by Congress.
> FISA orders and authorizations can be used to compel electronic surveillance and the disclosure of stored data, including content from services like Gmail, Drive, and Photos.
That's very different from prism. It's also why Google has spent a lot of energy trying to make it impossible for them to see the contents of your data. The government cannot conpel information Google doesn't have access to. I'm also not sure it's relevant for the topic of this post.
