I.e. now what would previously have been letters from the front might be sent as a text, phone call or E-Mail. Dead people don't pay for advertising revenue, so that data's likely being deleted soon after they're gone, or when their phone dies.
Yes some of these services allow salvaging the data of relatives, but most people aren't going to be paying whatever's the future Google extra money monthly to preserve grandma's multi-gigabyte E-Mail account. What would previously be letters from the front stored in a box somewhere will be stored alongside swaths of commercial E-Mail and spam.