Does making directly derivative works —in a way that wouldn't be allowed by fair use— really progress the useful arts or sciences?

I'm against these stupid-long copyrights but because I believe all human endeavours are a result of human society. Fair remuneration but not forever.

Yeah, I'm answering my own question. If society can't access work, they can't use it fairly or otherwise.

Everything is a Remix: https://www.youtube.com/watch?v=X9RYuvPCQUA

Yes, because fair use is a defense in court. This alone is enough to intimidate away most people from even contesting it. The result is that copyright conglomerates and some corporations take advantage of this by using a firehose of copyright claims.

The other factor is that people don't really behave according to copyright rules. People will habitually create copies of images all the time by uploading them to discord, imgur etc. Their intent is not to create copies, but to simply show it to somebody else, but because of some technical reason they can't easily do it without that.

Memes, specifically image macros, are likely suspect whether they fall under fair use. They can sometimes take the entirety of the work.

There are some other reasons like this as well that I can't recall right now.