Arguably the reasons there are more remakes and adaptations of existing franchises is specifically for value to accrue to those IP's, in a very siloed and narrow way with minimal cross-pollination across brand ownership lines.

Remakes and adaptations are a timeless part of storytelling though. Having a template for a popular story with the freedom to adapt it to a new time period and audience is how we transmit our culture. For example:

    Pygmalion (Greek myth) -> Pygmalion (Shaw play) -> My Fair Lady -> She's All That  
    Hamlet -> The Lion King
    The Odyssey -> O Brother Where Art Thou (and countless others)
    Emma (Jane Austen) -> Clueless

But wouldn't these adaptations still be allowed even if the original was copyrighted? Hamlet -> The Lion King has similarities but there's enough differences that even if Hamlet were copyrighted it'd still be allowed as a separate work of art.

They might be. NAL, but if a work is sufficiently transformative I think you can argue that copyright doesn’t apply. You might have to go through an expensive lawsuit to get to that point though.

Copyright has a chilling effect too. My wife is an art historian and publishes academic papers and books on contemporary art. Many times the artists are still alive and she’ll need their permission to reproduce an image of their artwork.

Technically, reproducing something for commentary or criticism, especially in an academic or educational context, would fall under fair use. But no publisher is going to risk having to defend that in court, certainly not for an academic work that isn’t going to make any money, so in practice you have to obtain (often expensive) reproduction rights from the rights holders.

The problem with remakes and adaptations of existing franchises is that they all basically follow the same safe and tested structure. So they are boring and feel all the same because they basically are.

I might argue that this phenomenon is too a byproduct of copyrights. In a world were everyone can create interesting things on any IP, there's no market for cookie-cutter adaptations. People watch cookie-cutter adaptations and remakes because it's the only way to experience the characters and worlds they like. If they had another option they probably just skip the reboot and go watch the new take from a different studio or director.

A lot of what made Disney so beloved is remaking and adapting existing works. There's nothing inherently wrong with the act of remixing, it is in fact the driver and source of a lot of great culture we've had the honor of experiencing over hundreds, thousands of years (yet particularly in the past 50).

What I don't understand why people seem to think Disney alone should benefit from existing works, and nobody else. Or that copyright being restricted to a single entity is the best way to ensure "good" works being produced.

Both can coexist.

Consider that Greek mythology or Irish fairy stories are basically different stories in the same "cinematic universe."

But... that universe isn't a monopoly. Many authors contributed. Stories were tailored to different audiences.

The cliche blockbuster remakes are corny because they are, but the concept of remakes, universes and sequels isn't bad.