A quantum gravity theory might not use the vocabulary of curvature or the tensor fields and scalar objects found in the Einstein Field Equations of General Rela

A quantum gravity theory might not use the vocabulary of curvature or the tensor fields and scalar objects found in the Einstein Field Equations of General Relativity, but that's not quite the same as "doesn't have to explain curvature". For the theory to be viable it would have to explain why General Relativity is such a good effective theory at solar system scales. One can do this by treating General Relativity as a theory which emerges in some limit of the more fundamental theory of gravitation (or everything). One can compare that with how Newtonian gravitation emerges from General Relativity as one takes c to infinity, or as one takes v^2/c^2 (where c is usually set to one; one can likewise expand in other small parameters) to zero. The first is the basis for the first section of https://en.wikipedia.org/wiki/Post-Newtonian_expansion https://en.wikipedia.org/wiki/Post-Newtonian_expansion The second section has more explanatory power: Newtonian gravitation emerges from General Relativistic systems when multipole moments are small and the distance to the sources is large. The key to the success of General Relativity compared to many of its competitors is that it very straightforwardly produces the Newtonian solution for the well-studied orbits of the Jovian system, while explaining the anomaly in the precession of Mercury's orbit. One would have to be able to show conditions in the new theory in which General Relativity emerges (and for which General Relativity has observational support), or the theory is not going to get much practical use in astrophysics or GPS-style engineering, even if it appears to get the microscopic details right. Practically[1] nobody -- there are several serious contenders like Loop Quantum Gravity -- who has developed an alternative theory of gravitation (or everything) has been able to show at all that General Relativity emerges from it. Lastly, because we don't have the technology to probe the quantum gravitation sector directly, but we do have the technology to probe General Relativity very finely (such is the topic of the article), I can't see how a failure to explain General Relativity's results can do anything but undermine quantum gravity candidates. - -- [1] People have proposed turning various constants into spacetime-dependent functions, and find that such adjustments can solve some things but generally have to vanish practically everywhere, so such theories are not viable. Among these are Palatini and others https://en.wikipedia.org/wiki/F(R)_gravity https://en.wikipedia.org/wiki/F(R)_gravity and Brans-Dicke https://en.wikipedia.org/wiki/Brans%E2%80%93Dicke_theory https://en.wikipedia.org/wiki/Brans%E2%80%93Dicke_theory. These families of theories usually show how General Relativity could emerge, but further investigation almost always shows that the parameters or features that distinguish these theories from General Relativity are incompatible with observation and so must vanish.