So when your electrician screws up and your breakers trips every time you run the toaster nobody is qualified to judge the work faulty unless they also fix the problem? The point being that it doesn't take an expert, nor does it require the ability to devise a solution to know when something's been done incorrectly.
You almost created an argument there, too bad you posted AC which will prevent us from being able to tell if the person who posted it ever returns to see the response.
Nevertheless, it does warrant some exploration. The point I was after is that merely saying something doesn't work is not at all the same as actually doing something about it. Your electrician example is pretty good for this; just about anyone can tell when they have plugged something in to a faulty outlet, but not everyone is capable of fixing the wiring. With the education system, we have a lot of people who recognize that something is wrong, but very few people who are proposing any kind of solution. We also have a few people who want to call in plumbers (educational equivalents of venture capitalists) when we need electricians (people with experience in education), apparently under the notion that wiring is pretty similar to plumbing.
The other problem though is that it is really hard to tell if common core has actually failed. Someone else pointed out there are three main components to common core; they really should be evaluated independently. Another thing is that at the start of the experiment no criteria were laid forth to evaluate success (or failure) which makes it that much more difficult to score. Finally, without having comparable control schools to compare to common core schools, it is that much more difficult to show what kind of "failure" this has brought on. Any time you change the system there will be turbulence.