A future where the darknet is the only place to find non-sanitized content on the Internet is extremely blackpilling to me, even if it turns out to be the only option.
I know Tor and I2P aren't what the mainstream paints them as, and that they are easy to use, but the idea of having to use something that is often associated with 1337 hax0rs just to access content that was common place on 4chan or even the darker corners of Reddit 10 years ago without showing an ID, just seems so wrong to me.
Also, many people don't realize how easy it is to de-anonymize users even if they are using Tor. Sites can use JavaScript or even CSS to de-anonymize users. Metadata can give clues of who people are. That's why the Tor browser discourages fullscreen use. You just know that governments are going to be setting up more honeypots where they try to catch even the most slight slips of OPSEC, if a future like this happens.
Not to mention that these darknets are still ultimately band-aid solutions because they still rely on the physical structure of the regular Internet and governments and ISPs can (and in the former case, have) block them via DSP. Supposedly, the Tor bridges hide the fact that you are even using Tor by making the traffic look like VoIP, but I feel like they can find a way to determine if you are using it, eventually.