The fact is that the original intent of the common core , was to address this very concern (number of topics). The problem, though, is that they didn’t actually cut anything (in math), as far as I can tell. Why this happened is tough to say. One complaint that teachers have about the common core is that they were developed by a very small group of people without input from teachers. Perhaps that small group didn’t have the heart to cut any topics.
Or maybe the committee, even if it was small, was unable to come to agreement on which topics should be cut. You see, the issue isn’t so much the size of the group or whether or not they got input from teachers, the issue is that the ability of that group wasn’t up to the task. Perhaps it would have been better if the task were left up to one very clever individual who understood the needs of teachers and of students and could be trusted to do this right. So, yes, I’m suggesting that rather than whatever group they formed, the common core standards would have been much better if they had just hired one person, namely me, to do the whole thing.
The ELA situation is more vexing -- they did brutally cut out a lot of stuff, but somehow ended up with almost as many minutely varied standards covering less ground -- but similar insofar as a small, insular team could work for standards writing, if they were particularly experienced, inspired and focused. That doesn't describe who we had working on Common Core.