We may not have flying cars, but we already have a one-size-fits-all educational system. Mainstreaming, where slower learners and those with reduced cognitive function are added to classrooms (with and without aids, depending on severity) brings up the bottom, and all but the brightest on standardized are discouraged from entering "gifted and talented" programs. Teaching is aimed at producing the maximum number of passing grades on standardized tests.
The top and bottom 2% are weeded out - charter schools or G/T at the top, traditional special ed for those who will never achieve. The other 96% are lumped together and the teacher is salary-bound to make as many of them pass as possible. That means standardized worksheets and test prep pretty much from day one. The result? The bottom 10%, which would require extraordinary help to pass, are dropped as a waste of effort, the next 30% get most of the attention to try and get them to make the grade, and the rest of the class pretty much floats for the year with little or no real instruction because they learn well enough from the books and videos to get a passing grade. Anyone in the top 30 percentile points is bored to tears.
There are exceptions to this, of course. Some teachers put in lots of extra time and effort, others are the truly gifted teachers who weave engaging lesson plans and get the kids interested enough to retain the knowledge and pass the tests without crazy drilling. But, for the most part, when your job depends on hitting a number and there's no accounting for whether you have the smart class or the dumb class you're going to get a rhythm down and stick to it. At least if the test scored come back poor, you can open you planner and show all the drills and fact sheets you went over showing you covered the material.
It's pretty damned sad.
(Oh, and as for private schools...have you seen the cost? It's unlikely a family with 2 children who aren't in the top 10% of wage earners are going to be able to afford 12 years of private education. The opportunity is there, but the consumers to support it are pretty thin.)