I’ve been writing about culture for six years, four and a half of them full-time. And while I’ve always been curious about the gap between Hollywood’s liberal reputation and the obviously illiberal results of its hiring and casting processes, 2015 definitely felt like a moment when the conversation changed. The discussion about diversity in the entertainment industry has never been so vigorous or so concrete, but this year also revealed just how far the fight for more representative pop culture has to go and how hard it will be.

Lily Tomlin, left, and Jane Fonda pose at the premiere for “Grace and Frankie” in Los Angeles in April. (Mario Anzuoni/Reuters)

There’s no question that 2015 was a year when the discussion about diversity in the entertainment industry moved from vague protestations to specific demands and actions.

Native Americans are dramatically underrepresented in popular culture. But despite the lack of jobs for actors of indigenous descent, a group of them walked off the set of Adam Sandler’s Netflix movie “The Ridiculous Six” to protest the demeaning characterizations they were asked to act out. After the Sony email hack revealed widespread pay inequities in the entertainment industry, Jane Fonda and Lily Tomlin, the leads of the Netflix series “Grace and Frankie,” took their negotiations with the streaming service public. Jennifer Lawrence vowed to be a more aggressive advocate for herself in pay negotiations in an effort to change the playing field for other women in her position. As Kathleen Kennedy unveiled her vision for the “Star Wars” universe, revealing major roles for women in upcoming films, it began to seem possible that having a female executive in charge of a major franchise might actually make a difference.

And most significantly, after the American Civil Liberties Union called for federal and state-level investigations into the hiring practices that result in a very small number of women getting directors’ jobs, the Equal Employment Opportunity Commission began a probe in the fall.

These are all encouraging signs, and it’s important that figures like Spike Lee are talking about the diversity fight in terms of specific reforms like a Rooney Rule for directors, rather than simply discussing desired outcomes without any sense of how to move the industry in that direction. But for all of these promising steps, 2015 showed just how much discussions about diversity in the entertainment industry have yet to resolve.

It’s become a truism of the diversity debate, for example, that we should aspire to see more women and people of color directing and starring in major franchises, like the James Bond movies, the Marvel Cinematic Universe or “Star Wars.”

Idris Elba poses in Cannes, France, in April. (Valery Hache/Agence France-Presse via Getty Images)

But would casting a black actor as James Bond open up space for that franchise to explore what it means for a black man to be raised in elite British institutions? Or would it elide his race in ways that rendered his casting less meaningful? Would a female director helming a “Star Wars” movie have an opportunity to cast a truly new eye on the world George Lucas created, perhaps by examining what it means for a young woman to train as a Jedi and facing different obstacles than her own anger and aggression? Or would she be under enormous pressure to turn out a conventional, marketable action movie? In other words, do we want to prove that women and people of color can make generic Hollywood action fare just as well as straight, white men? Or do we want to expand the range of what Hollywood can do to accommodate very different perspectives and priorities?

It’s also become clear that diversity in Hollywood is a moving target. Even as a number of majority-black shows became breakout hits, a report from the Writers Guild of America suggested that the number of African American writers on TV staffs had fallen slightly. The success of a Shonda Rhimes isn’t necessarily a proxy for the industry as a whole. Even if women or people of color got more executive jobs in Hollywood, that’s no guarantee that they would automatically help their peers up the ladder behind them or that talent agencies — which many sources have suggested to me are a major roadblock in the diversity fight –– represent or will fight for the women and people of color those new executives might potentially want to hire.

And none of this is even to mention the influence of foreign audiences’ preferences and huge franchises have on who gets to become a star or the project-based nature of Hollywood. A great year for African American film and television, for example, could easily be followed by years of drought if a few shows come to an end or a few directors take longer than expected to develop their next projects.

These are significant issues to resolve, and they are longstanding ones: Hollywood’s problems with racial discrimination are as old as the industry itself. And the Hollywood Production Code slammed shut the brief window of opportunity women had to tell daring stories about themselves and their lives — it’s never quite opened all the way back up, and it certainly hasn’t expanded as ambitiously as women’s roles in the real world have in the decades since. If Hollywood really wants to live up to its congratulatory self-image, the industry will need to find a way to reckon with its history. And advocates will have to keep up the pressure not just for diversionary crumbs, but for a whole new way forward.