Typhoon YouTube TV is about $45/mo now, and you can stream at least 5 separate shows at once on various devices for that price. It is NOT $45 per TV.
Rokus are pretty cheap, and/or Chromecast too. You'll need these for "dumb" TVs or TVs that are old enough that there is no YTV app for the device.
These devices connect to WiFi, so you'll still need that element of your existing system. You will not need your cable boxes, since everything will be internet based. Modem + wifi router is all you'll need. Modern Roku devices have excellent range and have performed wonderfully for me.
YTV has been excellent. I'm not missing any channels, stream quality is excellent, unlimited DVR. Hard to beat.