And a more direct answer to "Why hasn't anyone tried to .." is that many have tried to do that and failed - but the general public doesn't see that because such attempts tend to simply result in a wasted year and a wasted million, written off before even getting to a launch.
The failure point is content. If you wonder where to start - try to figure out the content deals, because all other aspects (technical, customers, design, etc) are much easier and can be solved if you have money; but without [good] content, your TV service is useless.
The failure point is content. If you wonder where to start - try to figure out the content deals, because all other aspects (technical, customers, design, etc) are much easier and can be solved if you have money; but without [good] content, your TV service is useless.