I'm not saying that technology shouldn't move forward, but that resolution is absurd.
Think of how much battery that will suck away, not to mention the graphics required to run a game in native res.
As for PPI, unless I see it in person, I can't comment on it. However, many people can't even/don't even care about the difference between 1080P and 720P on their TVs, so IDK why the typical consumer would care about this.
Why would the typical consumer care about retina? Marketing.
People don't care about the difference between 720p and 1080p because they both fall under the same HD umbrella.