Sadly, it wouldn't have made a difference - I've been watching this trend develop for around 14-15 years.
I really wish that I could say that leading with diversity wasn't tapping into a poisoned well outside of places like Tapas. I won't lie - @darthmongoose's information was a surprise (and don't get me wrong - I'm glad that what she said is true). Very clearly there is a community here that responds favourably to diversity as a leading marketing point.
EDIT: I'm going to add that I was WRONG in the case of Tapas, and that makes me VERY happy.
EDIT #2: I just added a revision both to the original post and the entry in my Writing Quick Guides to clarify that the discussion of the poisoned well is in regards to marketing to the general public, not to Tapas.
But, outside of here, the evidence of a poisoned well is mounting:
Disney sequel series Star Wars toys do not sell (http://www.rebelscum.com/story/front/Rebelscumcom_Presents_The_2020_Gentle_Giant_Ltd_QA_186744.asp). Further to this, I am the publisher of a book on Star Wars, and I can confirm that since The Last Jedi, demand for the book had dropped to a lower level (and this demand was steady for years beforehand).
Marvel Stage 4 has underperformed, and there is a downward trend of actual ticket sales for these movies (https://cosmicbook.news/thor-love-thunder-box-office-underperforming-eternals, https://www.fastcompany.com/90694476/why-eternals-underperformed-and-what-it-means-for-marvel, https://www.forbes.com/sites/dereksaul/2022/08/04/interest-in-superhero-movies-drops-poll-finds-worrisome-trend-for-disney-amid-marvel-slump/1). Since around Iron Man, a Marvel movie succeeding was just a given, and that is not the case anymore. Spider-Man No Way Home stands as a notable exception, but it notably wasn't marketed based mainly on diversity.
CBS' revived Star Trek performed so poorly that CBS's production partners tried to pull out of their funding contracts (I can't find the coverage at the moment, but I remember reading the articles on it, and it was one of the reasons why Netflix didn't carry Star Trek: Picard). Strange New Worlds may be their first unqualified success, and it's a throwback to the original series, and was marketed as such.
These are the three biggest examples. But when you see this many things with established fan bases whose only overlap at times is general genre that should be guaranteed successes under-perform and see decreasing returns, and the only common thread between them is diversity-based marketing...well, that's a clear indication of a problem with the marketing. One in decline, sure - Star Trek in the early 2000s got pretty mediocre, and it didn't need a poisoned well of marketing to lose an audience. Doctor Who under Chris Chibnall had such a low general standard of writing that I became embarrassed at the thought of showing it to my daughter - no poison well needed for it to lose its audience. But declines in performance across the board? There's too much correlation there.
If I had to venture a theory as to why the well is being poisoned, I think it's just two factors:
Attacks on fan bases. This baffles me - I never could have imagined attacking the people who are most likely to spend money on your product appearing as part of a marketing strategy, but here we are. And the problem isn't just that it happened across multiple properties - it happened across multiple MASSIVE properties, and was pretty much always associated with diversity marketing. So, the public in general saw repeated cases of diversity being pushed in the PR, followed by some fans saying "wait a moment - that's not how that character was written/we remember it/etc.", followed by attacks on those fans for racism/misogyny/etc.
Erasure of past successes. One of the things I've noticed about the modern trend is that the marketing for something like, say, Star Wars or Star Trek has to present what they are doing as the first time this diversity has existed. So, when Star Trek Discovery was first being marketed, Michael Burnham was being presented as the first black lead of a Star Trek show. This was nonsense - the first black lead of a Star Trek show was Avery Brooks as Benjamin Sisko in Deep Space Nine back in the 1990s (this was later revised to "first female black lead"). When the Obi Wan Kenobi show was being marketed, the claim was made that there had been no people of colour in Star Wars prior to the show, which was, again, nonsense.
Now, it should be noted that none of this is diversity's fault - this is the fault of people doing very public PR in what is sometimes likely to be bad faith. But claims of diversity is what it stuck to, and this isn't the first time something like this has happened:
There is a type of fedora called a trilby, which is known for having a thin brim. During the late 2000s and 2010s, this hat became associated with reactionary right-wing men's rights advocates, who tended to wear them while making videos and gathering in conferences and the like. This then associated the fedora as a whole with this sort of advocacy (not the hat's fault).
The Men's Rights Advocacy movement started out as advocacy for father's rights in family courts, where there was (and as far as I know, still is) a bias towards granting custody to mothers based on their sex, rather than their fitness as a parent (and quite a few children suffered as a result of this). This attracted virulent misogynists who very publicly used the label to identify themselves when they attacked women in general. The name "Men's Rights Advocate" became associated with the misogynists, forcing the actual father's rights advocates to abandon the term.
Now, everything I've seen about the public as a whole suggests that they don't care that much about the sex, race, or sexuality of a character so long as that character is well written. I don't remember anybody complaining about Forest Whittaker in Rogue One in the 2010s, or Wesley Snipes as Blade in the 1990s. It's the marketing that people seem to be having a knee-jerk reaction to, and when you look at the attacks on fans combined with the erasure of past successes that has been going on, it's hard to blame people for that.
As I said, I'm glad the well is not poisoned here on Tapas. But, out there, all the indications I'm seeing is that it's a very different story.
