As an online instructor of math and physics, I agree completely. If you're going to do it right, it takes a big investment of time. Also, since our class sizes are no more than 15 students, they get a lot of individual attention, probably more than average in a traditional classroom. The training our institution requires prospective instructors to go through makes very clear that it's not an easy way to make a buck. I've been told only about 6% of applicants make it through the process. Now without doubt there are some bad online instructors and there are schools whose priority it is to crank as many students through as possible, regardless of whether they belong there, but don't get the impression all online education is like that.