This is the principle of so called high pressure superconductivity, for example. The interior of neutron stars is considered to be superfluous as well. How is it possible, if their material is so dense?

This is the consequence of high environment density, instead. We know, the waves at the surface of mercury are smaller, then the waves at the surface of water, they don't penetrate the space beneath the surface so much, so they cannot be dispersed by it. As the result, they're less dispersed by such environment and the Aether concept is just the extrapolation of this idea to the infinite density.

After all, the idea, the vacuum is boson condensate or superfluid isn't very new in physics. You've probably missed a few important connections, here...