I actually think yes.
I get that 'harmful' is subjective, and authors should have the freedom to write whatever they want, but on the other hand...no one creates in a vacuum. Reality informs art, and art informs reality.
There's a reason that the push for diversity/representation is so important: 'harmful' content is never going to go away, but we can at least try to balance it out/contextualize it with stories based in decency and truth.
The 'damsel in distress' trope means less when it has to compete with stories starring female characters with agency and strength. The 'magic black character' stereotype means less when it has to compete with stories starring PoC with nuance and character depth and problems they solve for their OWN benefit.
And that's really all we need, for the cliches to look like cliches, and not like realistic standards that impressionable people might try to apply to the world around them. The only people who can make that happen are the storytellers.
Um, yes...basically, what I said above, but the other way around. People who write 'harmful' stories just to make a profit won't be motivated to do so if the audience refuses to consume them.
This is a bit different, I think...a harmful/demeaning message and a bad situation are not the same thing. The former holds up the content as ideal, or at least as normal; the latter simply portrays it. In the context of the story, it is just a fact.
The distinction, in practice, is very subtle, and when a creative work gets popular it can often get lost (for example, Romeo and Juliet...), but a careful reader can usually tell the difference between an author saying 'this situation is a good thing' and 'this situation is what it is'.