I think there are a few different things going on with critiques like, e.g., casting critiques (and ways in which live-action and books have different concerns).
To take The Danish Girl as an example. It's entirely possible that Eddie Redmayne - or a cis woman - could have played Lili Elbe in a compelling way that resonated with trans audiences. In a world where trans actors had equal shots at cis roles, this might not be a big deal, but we don't live in that world, so Redmayne having the role means a trans actor couldn't. That's a real issue of limited numbers of roles available, because the people writing the roles are not the same as the people playing the roles. With books, there are systemic problems in the publishing world that mean own-voices books often face more barriers and receive less marketing support, but at the same time, anyone can theoretically write a book representing their experience - they don't have to wait for someone else to write the role and then compete to get it. Whether that book gets traditionally published or widely read is a different factor, but live-action media are a collaboration between writers, director, actors, and others in a way that books are not. I saw a lot of discussion of whether Redmayne should have been cast; I have seen no discussion at all about who wrote the script (Lucinda Coxon; I don't know if she's cis or trans).
Which brings me to: The Danish Girl was, I think, a bad movie that did a lot to dequeer both Lili and Gerda and push them into a heterosexist, transphobic narrative that is not reflective of what we actually know about their lives. I also found the way Lili was written really...off...more like crossdressing fetishism in some ways, but I'm not a trans woman so I don't know if that's just me. Casting a trans woman as Lili would not have fixed the massive problems with the script. For that matter, someone else (trans or cis) might or might not have written a better script. Identity of writers or actors doesn't guarantee quality. (And if the historical reality HAD been what the movie showed...well, we'd have to deal with that, I guess, people are complicated and historical figures held all kinds of views we side-eye today? But when the historical reality is changed in those very specific directions, it feels hostile.)
(In case you can't guess, The Danish Girl made me really angry, although it least it sent me down a really interesting historical rabbithole about Lili Elbe and Gerda Wegener.)
So there's (i) access to work opportunities for marginalized people, (ii) physical representation in the sense of people playing characters who share their identities, and (iii) representation of stories that resonate with the people they're written about. The first two are fairly easy to measure, although not uncomplicated. The third isn't - different things resonate with different people regardless of whether they share identity with the actors/authors, and people who don't share an identity and can do also create things that resonate.
no subject
To take The Danish Girl as an example. It's entirely possible that Eddie Redmayne - or a cis woman - could have played Lili Elbe in a compelling way that resonated with trans audiences. In a world where trans actors had equal shots at cis roles, this might not be a big deal, but we don't live in that world, so Redmayne having the role means a trans actor couldn't. That's a real issue of limited numbers of roles available, because the people writing the roles are not the same as the people playing the roles. With books, there are systemic problems in the publishing world that mean own-voices books often face more barriers and receive less marketing support, but at the same time, anyone can theoretically write a book representing their experience - they don't have to wait for someone else to write the role and then compete to get it. Whether that book gets traditionally published or widely read is a different factor, but live-action media are a collaboration between writers, director, actors, and others in a way that books are not. I saw a lot of discussion of whether Redmayne should have been cast; I have seen no discussion at all about who wrote the script (Lucinda Coxon; I don't know if she's cis or trans).
Which brings me to: The Danish Girl was, I think, a bad movie that did a lot to dequeer both Lili and Gerda and push them into a heterosexist, transphobic narrative that is not reflective of what we actually know about their lives. I also found the way Lili was written really...off...more like crossdressing fetishism in some ways, but I'm not a trans woman so I don't know if that's just me. Casting a trans woman as Lili would not have fixed the massive problems with the script. For that matter, someone else (trans or cis) might or might not have written a better script. Identity of writers or actors doesn't guarantee quality. (And if the historical reality HAD been what the movie showed...well, we'd have to deal with that, I guess, people are complicated and historical figures held all kinds of views we side-eye today? But when the historical reality is changed in those very specific directions, it feels hostile.)
(In case you can't guess, The Danish Girl made me really angry, although it least it sent me down a really interesting historical rabbithole about Lili Elbe and Gerda Wegener.)
So there's (i) access to work opportunities for marginalized people, (ii) physical representation in the sense of people playing characters who share their identities, and (iii) representation of stories that resonate with the people they're written about. The first two are fairly easy to measure, although not uncomplicated. The third isn't - different things resonate with different people regardless of whether they share identity with the actors/authors, and people who don't share an identity and can do also create things that resonate.