Absolutely. I'm spending a lot of time on my 11yo's education right now, but I'm not deciding the scope of what needs to be covered or what materials would be best for teaching those skills. I'm not picking the books for her literature class and developing the writing assignments that point to the important elements of those books as they relate to the state standards. And if she gets stuck on something that I don't have the skills to help her with (which, granted, isn't a major factor with a 6th grader but would be important if she were a few years older), there's a teacher available to answer questions. I'm just making sure the work gets done, like helping with homework but taken up a notch.
I think the word "threat" is being used in two different senses here. I don't think most parents who are talking about homeschooling are directing their musings toward the school district except in the sense of trying to understand what school is likely to look like come September. At least the ones I know aren't. Their intent is not to threaten, but rather to gather information to be able to fully understand their options for the fall.
But schools nevertheless are threatened by that kind of thinking because it carries the consequence of lost funding, which could be potentially devastating at a time when their costs are almost certain to rise and state budget shortfalls may translate into cuts to per-pupil funding amounts. It isn't popular to say out loud, but childcare is one of the core social functions of schools - secondary to the educational function but nearly as important to many families - so the loss of that function is going to mean schools have to find other "selling points" to keep families from seeking out other schooling options that might be more able to adapt to current conditions, and that does pose a potentially existential threat to many schools.