You make some good points, but the overall message feels too defeatist to me. I've written a lot about these issues, on Wilders Security Forums, on Hacker News, and on the IVPN website. I believe that one can claw back as much privacy and anonymity as they want. And they can do it with setups that are workable and robust.
I agree that trusting companies that promise anonymity is dangerous. It's essential to distribute trust among multiple providers, such that compromise would require collusion. That's how Tor is designed.
Regarding "illegality", I broadly reject government authority. I'm a nonviolent and peaceful guy, unless attacked. But I refuse to worry about the legality of whatever interests me. As technology advances, the Internet will become the most fundamental reality. And so we must steadfastly assert its independence.
Many darknet services have indeed gone down in recent years. However, in all cases that I've looked at carefully, there have been glaring OPSEC failures. We can learn from those failures, and build stuff that won't get pwned so easily. I've written a long article, "Online Privacy Through OPSEC and Compartmentalization", which will appear on the IVPN website within a few weeks.