Earlier quoted context omitted.
Encryption with customer managed keys solves that pretty easily. It also solves any ethical questions with regards to furnishing data to comply with warrants. This creates a new problem of managing keys, of course, but that's been solved many times now in other parts of the industry.
There are numerous logistic issues with this approach. How would you implement a feature where users could log in to view the footage while away from home? They would need the decryption key, and if the server doesn't have it how would they get it? The only secure option is from the device itself, which is a pretty big UX challenge. However, worse, features that use AI to detect movement/people/etc can't be implement…
But yeah, I imagine you'd have a passphrase/key that can be found on a new device, perhaps via a QR code, and then signing into a new client device would require you have access to the old device to approve it/allow the private keys to transfer between the two, etc.