What prevailing theory in scientific circles do you think is likely to be replaced with a new understanding by 2050?

I am surprised of the fact that nobody wrote neoclassical economics

Is there a prevailing study at the moment? I have been led to believe there are some more empirical models in heterodox economics?

dark matter and energy are sorta placeholders and I think by then we will have a good idea of what they are.

You're more optimistic than me, especially when it comes to dark energy
- I feel like we have had some alternatives that have come close and hoping it all comes together.
Like Einstein adding the cosmological constant to his equations because he initially couldn't conceive of the universe expanding, and the equations wouldn't work otherwise.

The idea that human pharmaceuticals should be tested on animals before humans. The only real purpose animals serve is cost (you have to pay people to test your stuff and have insurance in case something goes wrong) and to ensure it's not obviously lethal or has permanent side effects before going to human tests, and even then you can't 100% prove it won't be harmful to humans with just an animal test. Dfferent species have wildly different physiologies and biochemistries so an animal test means very little in the context of effects on humans. It's really frustrating to see news outlets take a mouse test result and immediately assume it will work the same way in humans, not to mention the ethical implications. We're already developing alternatives to animal testing and I'm really hoping it goes obsolete within our lifetime.

The only real purpose animals serve is cost (you have to pay people to test your stuff and have insurance in case something goes wrong) and to ensure it's not obviously lethal or has permanent side effects before going to human tests,
Holy incredibly wrong.
or as it goes,
mice lie and monkeys exaggerate
It seems likely that simulated testing (in a computer) will be mature by 2050, it's under development now.

The timeline of human civilization, specifically the Neolithic Revolution that brought farming. From what I understand there is growing evidence that is not yet accepted by mainstream scientists that humans were somewhat more advanced much further back in time than previously believed.

Reading Graeber's Dawn of Everything and the history of the many "failed starts" of agriculture is so interesting. As well as why humans actively avoided it in many cases.
- Damn it! Another book for the list!

Always felt the cosmic inflation theory was a place holder until we better understand the early universe.

That there is just one big bang happening at a time.

I have a book on my to read list that delves into all the ideas about the "big bang" and how a lot of scientists are convinced that there were are and will be more "big bangs"
It's called "Battle of the Big Bangs"
I learned it from Alex O'Connor's "Within Reason" podcast episode 115
- I mean that there are more than one physical "universe" in the same physical space, they're just so far apart from each other that the gravity and bangs aren't close enough to have much effect on each other.
  We're just experiencing another iteration of "Earth is the center of the universe". We figured out something like the big bang might happen and assumed it was the edge of all time and space. Once again putting us at the center of reality.

that climate change fucked us

Round earth…

I mean, "round" is a non specific term already not used in science to describe the Earth. The earth is not a sphere if that's what you mean, they call it a spheroid because it's slightly distorted from the centripetal force of rotation and the surface is kind of rough.
- To be replaced with flat earth.
I wonder if there's an exact definition of "round", and if the Earth matches it. I mean, plenty of bumps in this sphere.
- If you're just looking at the bumps, then earth is flatter than a pancake. Literally.
- I read somewhere that the bumps are way less than what is on a basketball were it scaled up. Each bump being taller than Everest.
- Mathematically it is obviously not a perfect sphere, but then again I don't think such a thing exists. Not one made of matter, at least.

Dark matter and by extension the general theory of relativity.

The model of the solar system as planets rotating mostly within a flat plane around the sun, will become something more like the sun being akin to a bullet with a ballerina dress (to represent coronal aura and discharge) with the planets spiralling along with it but slower and trailing just a little behind. It will also include more space properties that aren't as well known like massive gas bubbles and a non-static gravitational floor, as well as man-made spacecraft and satellites. I don't know actually know what the current prevailing theory is. there's a lot of assumption here, plus imagination of how I believe things actually are, with no real certainty or any supporting evidence.

The model of the solar system as planets rotating mostly within a flat plane around the sun
This hasn't been the prevailing theory in a while. Actually, that's true for most of the simplified models we learned in elementary school. What you describe is quite a bit closer to the prevailing theory.
- Oh, well that's good to know. Thanks! I guess I need to update my own knowledge of what prevailing thought is.

Einstein theory of relatively and the theory of evolution and the theory of space

Am curious, why replace them and would you have an idea of what should they be replaced with?
- The theory of everything?

Not really sure if likely, but I think we're due for some connecting of quantum physics and regular physics into one theory. I'm optimistic, so within the next 25 years doesn't sound that unrealistic.