Note that the main motivation for modifying dynamics is not to get rid of DM, but to explain why the observed
gravitational field in galaxies is apparently mimicking a universal force law generated by the baryons alone. The simplest
explanation is, of course, not that DM arranges itself by chance to mimic this force law, but rather that the force law itself is
modified. Note that at a fundamental level, relativistic theories of modified gravity often will have to include new fields to
reproduce this force law, so that dark matter is effectively replaced by “dark fields” in these theories, or even by
dark matter exhibiting a new interaction with baryons (one could speak of “dark matter” if the stress-energy
tensor of the new fields is numerically comparable to the density of baryons): this makes the confrontation
between modified gravity and dark matter less clear than often believed. The actual confrontation is rather
that between all sorts of theories embedding the phenomenology of Milgrom’s law vs. theories of DM made
of simple self-uninteracting billiard balls assembling themselves in galactic halos under the sole influence of
unmodified gravity, theories, which currently appear unable to explain the observed phenomenology of Milgrom’s
law.