A simpler, less ambitious alternative is Clickbait Remover: https://github.com/pietervanheijningen/clickbait-remover-for-youtube
It replaces thumbnails with stills from the video. You can select between beginning, middle, and end.
It doesn't change titles but it lets you force capitalization to lowercase, titlecase, or sentence-case. Keep in mind that this has no logic to retain capitalization of proper nouns no matter which option you choose. I set mine to lowercase just to have some kind of consistency, because I got sick of random ALL CAPS TITLES.
I haven't used DeArrow myself. Crowdsourcing titles sounds interesting but I appreciate that Clickbait Remover behaves exactly the same way with 100% of videos.
30 years ago, maybe. Post-Napster, not relevant. Most online piracy is non-commercial now, and it's still illegal across most of the world.