I was not taught "the one-size-fits-all method" of teaching, whatever that means. From my personal experience, and multiple encounters with instructors on various levels, including the community college where I taught before I moved home, I know that most educators learn to assess how each student learns, then to explore methods that most facilitate each child's ability to grasp the subject matter. Furthermore, I've had the distinct honor of having students share with me their methods of solving different expressions, which has given me opportunities (teachable moments, if you will) to ask these students to 'teach' their methods to our classes.
Is "better schools" your euphemism for charter schools? Just FYI, I attended a private university (Rice U. in Houston), and I experienced first hand a rather poor example of an instructor in Cal I, from whom I learned not ONE scintilla of calculus. In other words, "better schools" is not directly correlated with "better teachers."
Finally, I didn't get the impression that the engineer 'restricted' his "kid's" learning. And, your observation -- "it would have taken him five minutes on google to learn the process being taught" -- completely misses the point. The last time I explored a list of polymaths, Gates wasn't on it. And, math is the oldest game our species has invented--so, I trust that the methods we've developed to 'teach' math have yielded excellent results (other than Einstein, Curie, and the better known scientists). I'd like to hear why Gates and his cronies feel it's necessary to completely revamp how we teach math. Oh, but then, that presumes we are going to discard the 'several different ways of doing basic math'?