Wireless is still cheaper
sounds like you are looking for is a MOCA solution (multimedia over coaxial) and they are still a bit pricey. Looking at about 150-200 per room from what I've seen (looked at it a bit cause my house is wired that way). You could set up wireless with a repeater and be much less expensive.
Sure, understanding today's complex world of the future is a little like having bees live in your head. But...there they are.