Ultimately, I think the issue with common core math is that the way they test it isn't great for kids who aren't wholly motivated by good grades and teacher praise. The "I did what you told me" crowd will always go for the food processor, because "what you told me" is cut up an onion. Asking kids to teach a fictional person how to do the problem might help with the motivation to do it the common core way, or maybe introducing a problem that is too hard for them to reasonably brute force in their heads (also how you spot the autistic math savants early lol).
I've got two kids in school right now, one is flying through it and one still hates the show your workiness.