I think the biggest misconception is that a PC needs to be expensive to be good. I recently built a computer for £600 which will play will play the latest games at 1080p no problem.
I could have made it cheaper if didn't buy a high quality PSU, SSD and a DAC.
Higher frame rate didn't get rid of split screen, it would be better to say that didn't want to compromise on both graphics and frame rate.
Split screen could have been possible but graphics would take a hit since you have to render the world several times depending on how many players
I think the main reason why games aren't running at 1080p60 is the as consumers we have had some pretty big expectation on how much of a leap the current gen consoles should be graphically compared to the last generation.
Developers are expected to make more visually pleasing games and because of that compromises have to be made.
While I agree that most of the games they make are lackluster, the games developed by blizzard are really well made