Albert Einstein's stated and demonstrated goal was the
formulation of field equations along the same lines as
Maxwell's but with more generality than Maxwell's with
the hope of including the force of gravity and inertia.

Did he succeed ?
In demonstrating that gravity and inerta are related
to electrical and magnetic effects and are subject
to the same delays and laws of conservation. The
prediction, in the Lorenz gauge, of gravity's effict on
nuclear resonance (Pound-Snider, GPS presets )
seems a quantitavive success, even if the sign is reversed.

In demonstrating a qualitative mechanism on par
with that of Maxwell's equations for light? If Tajmar
and de Matos is repeated and GP-B doesn't frame-drag,
then we'll have to conclude Einstein overlooked a
plausible mechanism, known in his career. (London, Casimir)
That would come as no surprise, as he overlooked the mechanism
of observer dependent light speed, preferring a mathematical
absurdity to leaving an open question. (P. Langevin)

Sue...