I certainly don't think transcribing an old piece should mean that you now own the piece for the next 160 years.

You don't own "the piece", you have a copyright claim to the specific parts you contributed of the specific arrangement/transcription you produced for the duration of copyright. Someone else can take that original work and create their own transcription/arrangement that you would have no claim over. ContentID is unable to reliably distinguish these two.

I don't see the difference. It means that if you transcribe a piece, I can't play the piece you transcribed based on your transcription for well over a hundred years. That's the bullshit.

The fact of copyright is different from the term of copyright. If we changed the term to 1 year tomorrow, there would still be arrangement and transcription copyrights. I also dislike the term, but it's a separate discussion.

I think it would be reasonable for someone to own future performances of a piece based on a transcription they made for a year, or a couple of years. I don't think it's okay for them to own it until 70 years after their death. Given that the term is what it is, it is unreasonable for transcriptions to be covered by copyright. The two things are inseparable.

No; if you create your own transcription, and it just happens to be identical, you own the copyright on your transcription. You can't steal someone else's, but you aren't forbidden from making your own, even if the end result is the same. (Better be able to prove that you made it yourself though.)

Transcription takes time and effort. Time and effort equals a copyright.

You start your message with "No;" yes the rest of your message does not refute anything I said.

This is so confusing. What stops people from copying music verbatim (with little effort) and obtaining copyright? And once someone has done so, if I try to do it too how can I claim I was transcribing the original and not the copy, since it’s identical? And if two identical transcriptions can exist, how to adjudicate which one to credit?

Copyright isn't exclusive, so the original rights holder you derived from would still have claim. You only have copyright on the derived work over the creative input and changes you provided, if any. If two people independently make the same creative changes, they both have copyrights on distinct works that happen to be identical. There's a well-known blog post on this subject called "What colour are your bits" (https://ansuz.sooke.bc.ca/entry/23) that goes into more detail, but the gist is that the copyright is not solely determined by a work's representation in the world, but rather by the process to create it (of which the representation is simply a product). If this needs to be adjucated, it's done by the courts.

This is true, but I believe exceedingly uncommon. There's a requirement for a creative element, and if there's only one way to adapt the music to a modern piano it shouldn't fulfill that requirement and be eligible for copyright at all. I would be unsurprised if copyrights like that existed, though.

If it were at all common, copyright would cease to function. E.g. someone could, in theory, write Romeo and Juliet word-for-word from their own imagination and then apply for a copyright. How on earth would enforcement work? There's no distinction between the copyright-free Shakespeare version and the newly copyrighted version, so do performers get to choose which version they're acting under?

Music has, through various court decisions through the years, gained a particularly arcane and arbitrary set of rules on what parts of a piece are copyrightable, and to what extent. It's a mess, as some parts are overly-protected, like the layout of the music on the page (unlike the typesetting of a book, or the font used!), and some under-protected in comparison, like the rhythm of a song compared to it's melody (which has a particularly arbitrary rule of 7 notes long). Though, to answer the question of the last part, if that version was copyrightable, it depends what book the performers are using! Though again, it could be that the essence of the performance is not considered to be a violation, even if photocopying the book would be, depending on what form any differences take.

If you're concluding copyright is impossibly complicated, vague, and confusing and the only reason the system works at all is because hashing out the details in court is either a nuclear option between two large companies, or enforcement on a large scale against small actors is basically impossible (but will unpredictably come down like a ton of bricks on some unlucky individuals), then you'd be right!

They don't own the piece. Anyone is allowed to transcribe the old piece for themselves, and then own the transcription they created.

But there'd be a finite number of ways to transcribe a piece. This someone would be able to claim the only ways to faithfully play the original public domain piece.

In that case, the law is not incompatible with you both owning your own transcriptions, even if they are identical. You might need some proof that you created your own if sued, but that's the copyright system.

Why not copy and say it's independently created? It does make it incompatible.

Same difference. It makes 0 sense that they own anything played based on the transcription for 160 years.

Irrelevant. All playbacks of the piece will be copyright-struck, regardless of the transcription used.

How can YT possibly arbitrate who transcribed/arranged a piece of classical music?

They don't. ContentID makes the claimant determine if a counterclaim is valid or not. YouTube forwards the messages, diverts revenue into an escrow bucket for the duration, and washes their hands of any decision-making in the matter after the automated notice.

This, i argue, has nothing to do with the amount of work, but everything to do with the simplicity of proving a copy.

A specific arrangement of words, music, or light (in the case of film) are well protected. Painting & sculpture, perhaps less so; fashion, dance, and architecture, sweet fuck all. Which all have as much if not more creative input than an arrangement.

How I think they should be handled? Same as fashion or architecture, only direct copies in the same format are protected, everything else is derivative.