I remember that they'd pack the executable with Themida with the highest possible settings in order to complicate reverse engineering.

Not really a huge hurdle nowadays, but they used to have the VM and anti-debug detection ratcheted up all the way and it would trigger when I had IDA open. (I believe it was a findwindow check)

I wonder if there'll be a renewed push for this in the next decade. At the moment it's pretty pointless given the widespread continued existence of headphone jacks which have a pretty big analog hole, not to mention the continued existence of stores selling DRM free protests after the backlash in the 00s

The analog hole isn't going away. At some point, the audio signal needs to get decrypted before going into the electromagnet that drives speakers. Even if you can somehow protect the electrical and magnetic signals, capturing a high quality audio signal from actual aucistic waves in the air is much simpler to do than capturing a visual signal from the light being emited from a monitor.

I mean, it's pretty pointless anyway. How long did HDCP 2 last? A couple years?