This USA Today article reports an increase in home schooling. In the last five years the number of home schooled children has increased 36% and now represents about 3% of school-age children.
When I was a child almost nobody was home schooled unless they were severely handicapped in one way or another. A few non-Catholic youngsters with "behavior problems" were sent to Catholic schools so the nuns could rap their knuckles or to military school so the upperclassmen could beat them into submission; I had one cousin in each category.
Of course, when I was a child our teachers were not unionized. Oddly, the public schools were held in higher esteem then than is the case today. Can these factors be related? Instead ask, can they not be related. Who has higher esteem, professionals who work for the love of their calling or wage slaves who periodically go on strike?
Another relevant factor is that some of the subsegments of the population today having the most children are the same subsegments of the population placing the least cultural emphasis on education. The preponderance of such pupils in a school can be a motive for parents who do care about education to home school their children.
Whatever the causes, I believe we can conclude that the public schools are held in lower esteem today than in was the case a few decades ago.
