If you live in town, even in a very rural area you typically going to have at least one, maybe two options for decent internet even if the cost might be absurd compared to areas with more competition. The further you stray out of town though, your options might disappear entirely leaving you with options like satellite internet or mobile hotspots.
When my mom was teaching through Covid she had at least 2 or 3 students in class (class size varying between 15-25 students) that either had no internet at home or their internet was not sufficient to handle a video call.