He's referencing that we have early 20th and late 19th century case law about third parties holding documents, etc, that is used to make everything sitting at a cloud service subject to subpoena without a warrant (email, etc, too).
There's all kinds of precedent that was based on sane tradeoffs for the 1800's that doesn't make sense anymore with the more complicated ways we transact and interact and with the ability of technology to commit mass surveillance.
Attitudes have changed a lot.There is an episode of Yes Minister where the minister does not want to push a shared govt database law because of privacy concerns. Another where the idea of ID cards is called political suicide. Absolutely true at the time, but the former is happening, and the latter is still not with us the UK but its no longer unacceptable to push the idea.
Kids are growing up expecting to be tracked (a lot of parents use "apps" to track what their kids do) so it will become even more normalised. People are used to being tracked as the tradeoff for map apps. There is a lot of surveillance anyway (CCTV and face recognition, number plate recognition, paying by card) so its already normal