Perhaps capture of audio and video from places lacking legal expectation of privacy.

Buying conversations from listening devices at live nation sports venues or clear channel airports.

Spooky, but probable.

Maybe there are troves of data yet to be unearthed, or needing extraction from legacy media formats. Orgs aren't desperate enough to do that kind of schlep, but soon enough.

Like archives of terrestrial AM/FM or even HAM radio up for grabs. Going backward to go forward.