Online teaching is not as effective as in-school teaching. Take chemistry for example. There are few homes equipped with a chemistry lab and shelves of chemicals. (Yes, that makes a difference.) There are no orchestras in the home. That impedes teaching music. Few homes have machine-equipped workshops. That makes robotics and other STEM subjects stall out.
Home school advocates tend to think in terms of the 1800s or early 1900s subject matter. There is so much more to learning than study and tests. Hands on work is actually required.