The same could happen for video recordings and their screenplays.
I think maybe the "works for hire" regime needs to be changed such that employees own the copyright to their own contribution to a work, and the employer just gets an automatic perpetual license only to works created while on the job, exclusive only as long as the employee remains employed, and the final aggregated commercial product is a derivative work from many sources. So if you can reassemble the same team of actual humans as the original, you can re-do the work of putting their contributions together, and acquire a new copyright on a new aggregate that could be nearly identical to the older aggregate.
So you only hold a monopoly on a movie as long as the majority of key contributors in that long credits scroll at the end continues to work for you. If you fire too many people after production wraps up, particularly the script writers and scene planners and digital modelers, they could get together, compare notes, and do a shot-for-shot remake at a fraction of the budget, because their part of the work has already been done, and you lost exclusivity when you fired them.
That would surely invoke a new form of Hollywood Accounting, but at least it would encourage creators to create works with some durance in preference to consume-once ephemera. And you wouldn't end up with great artists in poverty even as their works make their current owners heaps of money.
It is still important work to turn an artwork into a viable commercial product, and to assemble and manage teams of artists to great something together greater than what could be produced individually, but that added value should not make the middleman the sole gatekeeper for the source works, forever.
True, because every ass and his dog pirates music, thus the income from selling music is severely diminished. The amount of time it takes to produce/compose/record etc. music is not exactly trivial, and if you have to tour constantly in order to be able to pay the bills, then finding time and energy to create some new music to perform whilst on tour becomes quite problematic. Your "most artists don't care" statement is a crock of shit! Perhaps large established artists may not care so much, but if you're talking about "most artists" then they do care that income from their craft is being denied to them.
In any case, "album sales" is a very one dimensional view of the world. Even if fans were to pirate music, there is no way to pirate live performances - and exposure is one such way to boost sales of live performances so lost sales in albums is a very narrow slice of the entire ecosystem.
All I can proffer is anecdote that as bandwidth and the ubiquity of Internet increased over the years, the sales of music via the label I'm involved with diminished. All the while our artists and the label itself became more and more popular, so it seems entirely counter inuitive that sales should have been dropping.
The thing is there's just so much music now. The artists you represent may be more popular but there's so much more competition for people's money. There's music i've bough I enjoy from artists whose shows i'll probably never get to see. I spend a lot of time listening to concerts and such these artists freely post online, i'm enjoying their music, legally, but I haven't paid for it.
There are a lot of things contributing.to lower album sales. Piracy, while i'm sure contributes doesn't seem to be the biggest problem. Plus i've been hearing this since I was a kid and cassette tapes were being blamed for killing the music industry because people could just record anything they want off the radio or a friend's cassette so album sales were dropping.
https://www.statista.com/chart/12950/cd-sales-in-the-us/
Conversely, Napster was released in 1999.
I recall a report that showed that p2p networks acted primarily like a broadcast medium, which tuned to the most popular works.
The entire free content model has arisen because of tacit acknowledgement of that fact.
Youtube, hell everyone, applies those lessons today.
It's just more convenient. "Hey Siri, play the latest album by X" still works. Thank God.
Albums are only dead for artists who have to use filler to make the one hit song they managed to come up with fill a CD.