@strandednomore: I agree, the questions you ask are difficult ones. There is no easy cheap solution, nor any solution which will suit all families.
I do think it is useful for parents to be well aware of the advantages and disadvantages of the alternatives available in order to make an informed choice. In terms of finance, lifestyle, and difficulty, I find home educating is similar to having a parent stay at home with children in the early years. It isn't possible or desirable for everyone, but it is an option which appeals to many.
Those parents who find it an enormously painful wrench to return to work when their children are small will often explore alternatives in some detail to see whether there is any way to change their situation. Likewise, I think parents who don't feel right about sending their children to school at four may feel more comfortable about their decision if they know either that there is no realistic alternative for them, or if they have looked into the alternatives and have decided that the benefits of school outweigh the disadvantages.
Sending a child to school should be a conscious decision based on what's right for the whole family. For some people it is. But for a great many, it is simply something that happens to them without a decision having been made. Some of my friends describe having been swept along with the tide, sending their kids to school because it was "the done thing" and then feeling a vague sense of dissatisfaction.
Having a choice is a powerful motivator. I can remember work situations where I was very unhappy, but I always knew I had a choice of leaving. Sometimes I left and sometimes I stayed, but I never felt trapped.
Sorry, I'm rambling. I'm trying to make the point that it's good to know the facts about school and the alternatives, and to give it plenty of thought, regardless which choice a parent ends up making. That might sound patronising, but I really do think school is accepted too readily by many people who might prefer home education.