The scope of a scientific theory can affect its utility. A theory with a wider range of applications is also scientifically more robust in that a single system is less arbitrary than a hand-chosen collection of smaller systems, the wider realm allows more opportunities for falsifiability, the reduced number of different laws is favoured by Occam's Razor, and a more unified system also scores points for compactness, design elegance and efficiency.
General Relativity and scope
The C20th theories of general relativity have limited scope. GR1916 / GR1960rdoesn't successfully mesh with particle physics, because an attempt to model particles as small gravitational sources leads to an acoustic metric and a different set of equations of motion to special relativity, which GR1916/60 assumes to be correct. although C20th GR has been extended to deal with an expanding universe, it cannot cope with large scales consistently, because the causal structure of a cosmological horizon is acoustic and does not correspond to the theory's black hole horizons - the Hubble shift law is also not the shift law of special relativity. , and the behaviour of black holes under C20th GR, if we believe quantum mechanics, is qualitatively wrong.
While we can attempt to firewall C20th GR from these problems by declaring any conflicts with QM with regards to cosmology, black holes or particle physics as being due to a different, intrinsically quantum level of physics which Gr does not need to agree with, these measures reduce the realm in which GR agrees with the evidence, while being significantly different to updated Newtonian theory.
By comparison, an acoustic general theory uses the same equations for Hubble shift and motion, applies the same causal structure to cosmological and gravitational horizons, and appears to correspond to QM's statistical predictions for particle physics – where C20th GR insists that these limitations are natural and unavoidable, and acoustic general theory appears to have no scale limitations whatsoever
In terms of scope, the existing general theories do not appear to be in the same class as an acoustic implementation of general relativity.
Einstein's attempt to model particles as gravity-sources led to a redder "Newtonian approximation" of special relativity rather than to SR itself. Redder relativistic equations are a characteristic of acoustic physics.. To date, nobody seems to have been able to derive the SR relationships without assuming flat spacetime, and this has led to a "compartmentalisation" of physics, where where the physics of the very small is deemed to be the territory of quantum mechanics, and outside GR's remit.