Over the past few years I have talked to families with children who were homeschooled at one point and decided to send their children back to public school even after years of homeschooling. This usually happened as their children entered the high school years. For various reasons they decided that their homeschool journey had ended and felt no conviction otherwise. Talking with them more, they had some of the same initial reasons we had for removing our children from the public schools but they were solely pragmatic reasons. What I have come to realize is that our initial reasoning was also pragmatic. We saw a problem, found a solution, and like the results. This is not a bad starting point, but problems will eventually arise if this becomes the primary reason.
Please understand though, I believe we should be concerned for what is happening in public schools. This is a viable starting point in deciding to homeschool. The movie Indoctrination helps to bring this concern to the forefront by revealing the disturbing history of how public schooling came about, its underlying themes, and its initial opposition from Christians. No parent who watches this will think it is ever okay to have their children in government schooling again. The movie has a great starting point to bring forward the concern every Christian parent should have in regards to public schooling. But it is only the starting point.
The primary reason some homeschooling families cease to be homeschooling is the exact reason why many of us initially start homeschooling. Simply put, it is because we relied on results to determine whether something was effective or even whether it was biblical or not. If the results change, or the results we desire change then we can inevitably alter our direction. A parent who homeschools only for pragmatic reasons may put their child back into public schools for pragmatic reasons as well. The primary reason we are to homeschool is not because we want our children to be smarter or because we want to remove them from the ungoldy teachings. They are good reasons, but they are secondary to the teachings of Scripture. Deuteronomy 6 commands parents to be the teachers of their children. We are to instruct them in the ways of God, which touches on every subject of life. We teach them Scripture as well as a biblical worldview of all educational disciplines, which they will not find in public schools. In his message The children of Caesar, Voddie Baucham says "If we continue to send our children to Caesar for their education, we need to stop being surprised when they come home as Romans".