This chapter insists that there is no intrinsic length scale for liquid. Thus liquid can appear extremely viscous to objects on the nano scale. But I think we still need to be careful about the generalisation that a liquid can appear to have whatever viscosity we want just by changing the forces acting on the objects moving in the liquid. My hesitation comes from the fact that there are certain other limitations on the behaviour of liquids.
Imagine a liquid with an exceptionally high viscosity, where the critical force is a few kilonewtons. For particles moving under forces slightly lower than this, in the regime dominated by friction, motion will cease very shortly after the force applied to them ceases. All the kinetic energy of the particle would heat up the environment, as the energy is being lost to friction. Now, what if this heat was enough to cause the liquid around the particle to begin to boil? This liquid would never have a regime dominated by inertia.
This hypothetical liquid would have viscosity orders of magnitude higher than corn syrup, and I don’t think it reflects any liquid found in nature*. This example is not a situation that would come up very often, but it illustrates the flaw in thinking that any liquid can be made to appear to have any viscosity just by changing the forces acting on the particles in it.
*Pitch has a viscosity of about 200MPas, 40 million times more viscous than corn syrup. If pitch counts as a liquid, then this may be an example of a liquid with no turbulent regime. Pitch shatters when it is hit with a hammer, which may indicate what happens to a liquid without a turbulent regime if it encounters forces that would be in its turbulent regime.