I wonder how you can definitively say that "most home schooling parents do goof off." How many families have you observed?
I am currently a graduate student in Electrical Engineering and I know of two other homeschoolers beside myself in the college of engineering. I was the top graduate in electrical engineering, one of the others I knew was the top Junior (I reviewed GPAs for an honor society) and a third is a WW Allen Scholar and is a very bright, hard-working individual in Chemical Engineering. I'm sure there are others that I don't know about and I'm sure there are some who are not so hard-working or smart. But out of my sampling of three, "most" (none really) seemed to have parents who goofed off.
Being a home-schooler myself I have actually come into contact with a lot of families who home-school and of the 20 high-school-age children or so that I know personally in town, 4 of them were National Merit Scholars and the rest have been accepted with scholarships to various universities. Again, where is your proof of "most parents" goofing off?
I do not doubt that there are some. In my experience meeting with well over 50 home-school families and over 100 kids I never had that experience. Maybe because we were all like-minded, I don't know. I have only ever met one person that knew someone who did "goof off" as a home-schooling parent. So to provide an omniscient blanket statement that says "most home schooling parents goof off" seems quite a stretch to me.
Every parent I know who home schools, does it because they /want/ their children to have a better education, not because they want to be lazy. And with the amount and type of material out there, parents don't have to be geniuses themselves. My mother didn't know beyond basic Algebra but through the curriculum she bought I was able to learn Calculus at about 14. So please, don't make general accusations without any evidence. In fact, the evidence is quite the opposite than what presupposed notions would indicate.