I am generally anti-copyright; but it's not really a pro-creator policy to curtail copyright; it's pro-consumer.

> If everything older than, say, 35 years were suddenly in the public domain, available to be distributed by any of the distribution companies, and Hypothetical Media Corp had half the back catalogue that they used to, then surely that would make big conglomerates less interested in buying up Hypothetical Media Corp?

Doesn't your first point contradict this? If almost all the value of copyrighted works comes in the first few years, then no, curtailing copyright terms doesn't discourage buyouts, because the buyout is going to be mostly justified on the recent works held by the purchased company, not the residual value of its old works.

> Furthermore, current copyright terms are decades past the death of the creator.

It's important to recognize why this is the case - a lot of the hubbub around posthumous copyright comes from the fact that a large amount of classic literature often went unrecognized during an author's lifetime (a classic example is Moby Dick, which sold and reviewed poorly - Melville only made 1260$ from the book in total and his wife only made ~800$ from it in the remaining 8 years it remained under copyright after Melville died, even though it's hard to not imagine it on a literature list these days). Long copyright terms existed to ensure that the family of an author didn't lose out on any potential sales that would come much later. Even more recent works, like Lord of the Rings also heavily benefitted from posthumous copyright, as it allowed Tolkien's son to actually make the books into the modern classics they are today, through carefully curating the rereleases and additions to the work (the map of Middle Earth for instance was drawn by Tolkien's son.)

It's mostly a historic example though; Copyright pretty blatantly just isn't designed with the internet in mind. Personally I think an unconditional 50 years is the right timeline for copyright to end. No "life+50"; just 50.

50 years of copyright should be more than enough to get as much mileage out of a work as possible, without running into the current insanity where all of the modern worlds cultural touchstones are in the hands of a few megacorporations. For reference, 50 years means that everything before 1975 would no longer be under copyright today, which seems like a much fairer length to me. It also means that if you create something popular, you have roughly the entire duration of a person's working life (starting at 18-23, ending at 65-70) to make money from it.

> I don’t see how this can be true. Reduced copyright terms mean price for old stuff goes down (to however much hosting and bandwidth costs). This means more funds are available for new content.

Because this syllogism doesn't hold. There's not a fixed pot of money that must be spent on content. If now every streaming service has access to a bigger pool of old hits, then they don't need to buy as much new content to satisfy their customers, and total spending on content will go down.

> If everyone can sell the popular reruns and holiday movies, then they stop being exclusive to Disney and Comcast and Warner Bros and so the only thing they can compete with is new stuff, forcing then to invest in new stuff.

Each service will just become sameier and compete more on their UX than their exclusive content. You can see this in music, for instance, where the big streamers already have more or less identical catalogues. Nobody is picking Spotify over Apple Music or Youtube Music due to exclusives, because there are none; so putting the content into the public domain is hardly going to change things.