Just like declaring piracy illegal stopped piracy and removed pirated materials from everyone's computers.
Everything cannot, in fact, be taken away. Don't propagandize yourself. Some things, like information, are free. Not even China can prevent all its citizens from accessing Western internet. USGov simply does not have the resources to find and audit every hard drive and USB stick in the country for illegal files. The internet cannot be censored 100% without literally cutting every cable and confiscating every radio.
The software that runs on my computer cannot, in fact, be restricted. It can be declared illegal, but there literally is no mechanism by which it can be enforced other than a government goon standing over my shoulder 24/7.
Some freedoms really cannot be removed without utterly implausible amounts of effort. Arguing otherwise is helping to erode freedom. So stop it.
Maybe we can each get assigned an AI government goon to look over our shoulders 24/7. Maybe each neuron in my brain will have their own subagent goon. Each mitochondria gets their own subagent government goon. The government will perfectly model my every move. They will perfectly model the smell of my asparagus piss aroma.
Remote attestation?
On PCs, the best you could really do is restrict access to certain websites on certain boxes with TPMs the users can't disable. Remote attestation can lock people out of your stuff, but not out of their own stuff. For that you need control of the device. Of course, most mobile phones aren't easy for the user to have control of, but most PCs still are, so long as you scrub the rootkits (e.g. windows) off 'em
it doesnt even work in the government's own servers to protect their own shit
You wouldn't download a car?
In Soviet Russia, one couldn't download a car. In modern America, cars upload you.