My question is, could they human eye possible evolve to be able to notice the higher number of pixels per-inch or not?
i theory it could, but it would take generations, if you follow evolution, but with humans its flawed because it use to be if the ability developed (see more detail) it would help in hunting or surviving and thus would be passed on to the next generation but with us now its anyone survives and anything gets passed on, so in theory yes, but in actual chance of actual happening its very unlikely.