I don't know how long the records persist, but presumably for things like video surveillance footage the decay period would be quite fast. For full-text contents, less speedy but still fast. I can only truly envision long-term collection and storage of metadata - and even then, it's a big question how much is feasible and reasonable to store indefinitely.
It's likely that for your security camera footage to be accessed you would have to be targeted. It's likely that such targeting would only affect footage in the future or very recent past. But I'd grant that pervasive attackers can probably capture exponentially-decaying single video frames from millions of cameras if they were appropriately motivated, and those single frames could go back quite far.
The real problem here is the existence of such a system creates a kind of panopticon [0], with chilling effects not only on activity and discussion contrarian to the current administration, but also any future administration that may have access to electronic surveillance records. Without knowing how long records are kept, it is quite plausible that a future authoritarian state will misuse past records to target civilians.
[0]: https://en.wikipedia.org/wiki/Panopticon