Google is testing a new Global Site Tag that can now automatically collect the information that the user submits on the website (like email and telephone). 

It seems that automatic data collection could be one further step to employ user provided data for tracking and attribution, with cookies going away. The automatic collection is only with Google Global Site Tag gtag.js and is not available when using standard tag implementation via Google Tag Manager.

What isn't clear at the moment is if the data will be made available, for instance to develop custom match lists or if it will collect the 1st party data then blackbox that info.

Interesting development and one to keep a close eye on for sure.