And, if something has improved in cables since the original RG-6 it is the plastic used for the dielectric. Discovered by accident in England, PE was top secret during World War II due to its use in radar cable. This was one secret the Germans never figured out. And polyethylene continued to be the plastic of choice well into the 1970s, when cable TV companies really began to penetrate the vast American wasteland. That was accomplished by foaming that plastic, putting bubbles of air in it.
Air is a much better dielectric than solid polyethylene.
In fact, air is second only to a vacuum. The first way to foam plastic is to do it chemically. The pellets of plastic are mixed with pellets that foam the plastic when heated. This mix must be very precise. The mixture is heated together and squeezed onto the center conductor.