One of the things I think works in Dark Sun's favor in 2026 is that there are new exploitations of the masses that weren't even imagined in the 1990s.
I can see a city state where the underclass has no consistent employment, but instead, they have to queue up each day, hoping to get piecemeal work a few minutes at a time. If they're lucky, they can get a few hours at a time. It's obviously a horrible system, but the upper classes talk about all of the "freedom" the underclass has and that this gig work isn't meant to be a full-time job anyway ...
And if WotC wants to get really spicy (they won't), they can have the poor fleeing war torn and unlivable city states being turned away by others that are scared of the impact of cheap labor and cultural change.
I think it's a setting with tremendous potential, even if the writers just have to lightly touch on some themes and leave space for DMs to lean into them on their own.