However this time science knows what this ether is and already performs some experiments on it, although doesn't recognize it as a valid state of matter.
Ether is multiquarks essentially. Protons and neutrons are the densest or biggest form of ether. A tetraquark sporadically appearing in experiments is a particle of thinner ether. Individual quarks are very thin ether. So far so good and it's just a matter of terminology.
There are a few interesting claims made with respect to ether that science can actually verify. One claim is that ether is a legit state of matter and everything is packed with it. This doesn't contradict observations because most of the ether forms compounds with no electric charge, so there's no electron cloud around them that we could detect. Second claim is that ether forms very complex compounds with very sophisticated structure. The most complex compounds are atomic nucleus, the simplest ones are the basic multiquarks, but there's a whole zoo in between. Ether isn't just 6 quarks with an occasional tetraquark, it's a whole periodic table. What do you think the atomic nucleus consists of? Ball shaped protons and neutrons? Is it because thats what you've seen on a textbook picture or because nucleus tends to spit out individual protons and neutrons on collisions? Take a look at the competing theories explaining the structure of nucleus and ask yourself if they look convincing.
If this guess is right, dark matter is huge clouds of mostly neutral ether that can't possibly interact with light, as photons have nothing to bounce of (unless an occasional photon hits a quark directly). Ether could form a ring of "asteroids" around Earth: it would affect trajectories of spacecrafts, but otherwise would be completely undetectable. We would see it as a mysterious deviation from the computed trajectory.
And don't confuse ether with aether. The latter is literally space and particles of aether are electrons, neutrinos and all that quantum zoo.