It's not that we can't model gravity at planetary-orbit scales; that's been done. The issue is that relativity (which addresses gravity) is a good model at large scales and the quantum "Standard Model" (which addresses the other three forces) is a good model at small scales, but these two models are incompatible with each other and no falsifiable theory that works at all scales has yet been found.

They cannot be "incompatible with each other," otherwise Nature would be "incompatible" with itself.

The models are incompatible with each other, which means that one or both are somehow wrong, or there is some boundary we can't fathom between the small scale and the large.

Wrong - we do know that the models are not incompatible. (There exists a consistent mathematical framework that includes both.) Me, I was referring to a simpler fact that these models are both pretty damn close to what Nature itself tells us.

Models are not nature.

We have a working model of gravity that is very accurate in an incredibly broad array of circumstances. You acknowledge this in your comment.

This is a scientific result. What are you trying to say?

I don't understand a lot about how the computer in front of me works (ok, I know more than the average person, but still I don't know a whole lot). Yet I'm still able to use it.

We understand enough of the effects gravity to describe most phenomena that are relevant for most other parts of science. From my lay understanding what physicists are missing is how to tie in gravity with all the other theories they believe are true. However the effects, whatever they are, are so small that we can in most cases just ignore them.

this pop sci article does address that: we have a good theory of gravity at macroscopic scale but none at the quantum level.

"Science is magic that works."

-K. Vonnegut

There'also Clarke's Third Law.

How does gravity impact photons and quarks? That’s the part that’s missing.

How? If I understand the question - just like everything else. (Bends light, for example.)

yess, but then the numbers that power quantum physics stop working. something about the renormalization group?

My incorrect understanding is something like: quantum models imply a uniform layer of “virtual” particle/anti-particle pairs popping in and out of existence. but if the space they’re in is curved like general relativity describes, then the pairs don’t find each and annihilate each other reliably and all your math trends towards infinity instead of towards zero. or something vaguely like that.

I'm still trying to recover from learning that gravity waves can be curved by gravity.