  Several theories of the glass transition propose that the structural
relaxation time {\tau}{\alpha} is controlled by a growing static length scale
{\xi} that is determined by the free energy landscape but not by the local
dynamical rules governing its exploration. We argue, based on recent
simulations using particle-radius-swap dynamics, that only a modest factor in
the increase in {\tau}{\alpha} on approach to the glass transition may stem
from the growth of a static length, with a vastly larger contribution
attributable instead to a slowdown of local dynamics. This reinforces arguments
that we base on the observed strong coupling of particle diffusion and density
fluctuations in real glasses
