I wonder if stuff like this can be thwarted by having a constant flow of encrypted junk traffic between two parties - only replacing the junk with real data (but not changing the volume) when they're actively communicating.

Obviously, this doesn't scale for something like social media. But metadata regarding one-on-one conversations using something like Signal could be effectively obscured.

Trouble is it's so difficult to know what your adversary is doing, it's better to switch to a different medium i.e. reduce dependence on the Internet (as I detailed in another post).

The fundamental nature of the Internet itself permits this behavior to go unchecked, there is no way for a user to know what is happening behind the scenes with certainty. We send out our private information (search queries, etc.) into this giant black box we have no control over. That's the crux of it.

That was not the case with radio or satellite TV, the ability to determine what people were listening to or watching on a mass scale was nearly impossible due to the laws of physics. As the system was completely receive-only.