If parents saw how students in K4-6th grade were being taught in schools, they would realize that teaching their own child these subjects is not all that difficult and in fact, it would be to the advantage of the child to be homeschooled.
Most parents shy away from home schooling because they're afraid that the child isn't going to learn what they should be. Those fears are easily quelled by requesting the curriculum and standards from the district. Every school district should have this available. Once the parent has this in hand, they can design the lessons to meet the standards.