I thought I bought a camera, but no DJI sold me a license to use it [video]

Wait until physical camera makers not only license you the unit, but also make everything you shoot belong to them, like software camera apps (e.g., Filmic Pro) do now.

DJI can just add some mandatory firmware upgrade process that offloads your footage to the mothership, and 99.9999% will agree to everything without reading.

Might be a realistic way for manufacturers to to implement a certified-taken-by-camera-not-AI photo feature.

That way already exists and it does not require licensing your footage to any third party.

Frankly, I find the justification you provide preposterous and dangerous.

The sad reality is that apparently many customers will find it believable (in the .0001% of cases when they actually read what they are agreeing to).