Home schooling is such a wonderful thing.  It allows us to protect our kids from evil and indoctrination.  It allows us to teach our kids how to learn, how to think, and to love learning instead of how to recite back facts.  It allows us to teach according to each kid's own learning style.  It allows us to spend extra time helping areas of weakness, following interests, and accentuating strengths.  It builds a closer relationship between kids and their parents because the kids know how much their parent is giving to help them.

For a single parent, homeschooling may be difficult (although I do know one single parent mom of two kids, one special needs, who homeschools her kids and loves it.  For a married couple, I think it is ultra rare that a family can't homeschool if they decide it is important.  There are a lot of costs associated with working (work clothes, eating out, gas, a 2nd car, child care, etc.) that aren't there if one stays home with the kids.  In many cases, cutting these expenses (and having someone home to cook from scratch rather than eating out or buying more expensive pre-made/cooked meals) doesn't make the family live much less especially if you take into account child care for multiple kids during working.

I'd recommend parents spend their time thinking "how can I?" rather than "reasons why I can't..."  You will be so glad you did.