Coriolis - I understand where you are coming from in feeling that we would be best to put our efforts into improving the existing system, seeing as that is the system that the majority of people will be using.
Unfortunately, it is difficult to find where to start where impact can be made.
Therefore, I think that we need to take it on a case by case basis, improving the system where we can from whatever position we are in, and also appreciating good teachers, admin and schools where we find them. However, I think it is a machine that is very difficult to impact and changes made take a significant amount of time to be felt at a ground level. It has taken about 50 years for those who signed the humanist manifesto during the 30s to see their philosophical dreams realized at a larger level (through placing themselves in various position of influence throughout universities and schools during that time period). I don't know if in the age we live in that can be sped up or not, due to internet and other resources and I'm not sure how to go about achieving enough agreement and solidarity about what changes need to happen for reform to effectively occur.
I don't know anything about the schools in Canada, but in the U.S. it is most effective to attempt improvements at the local level, even in a single school. Parents are the key to this since they are the taxpayers, the voters, essentially the customers and the boss. Most are not trained educators, but know their children better than the teachers, and at least some of them can recognize institutional stupidity when they see it.
The problem is that parents are generally too reticent or intimidated by the system to put their foot down or, heaven forbid, organize with other parents, even when they are very much in the right. I watched a neighborhood family single-handedly turn a school around by insisting that their daughter get what she needed. In this sense, it is just another flavor of making sure your children get what they need, but done in a public school, it has the potential for much broader impact. The problem is not so much state standards, which are not going to change, or even funding levels, though many schools are underfunded. It is how the resources are allocated, but even more the unnecessary impediments to learning that abound, and have nothing to do with state standards or money. Parents who complain are viewed as a drag on the school; even moreso those who attempt to justify their children's poor behavior or academic performance. Parents who make well-thought-out suggestions to address well-documented problems, on the other hand, may meet resistance, but can have an effect if they are persistent and work together.
Since when did we start expecting the government to even educate our children? I'm not even quite down with that mentality, honestly. If we are going to implement such a socialist program, why don't we also have funded health care?
We are working on it. The roots of our public education system predate the revolution. Originally, the purpose was religious education, and later, preparation for the workforce.
Do you think we would be better off having everyone educated at home? How many parents (mostly mothers) would this take out of the workforce? How strongly would the quality of education received correlate with family income? Is that even important? In the old days, the poor didn't need much education, since they were destined for factory, farm, or domestic work anyway. Sounds like a recipe for regress to me.
If you're concerned about the quality of learning at a certain school, I'd advise to monitor your child's learning progress (which is always a good idea anyway). If it is at all possible and practical, I would strongly advise for public schooling and against homeschooling. Being part together with other kids in school is part of the education, as is the whole complex of being and working in a class, having different teachers, having a dedicated place for studying and learning etc. etc. Add to the fact that teachers at schools are people who not only had years of formal training but usually have a lot more experience in teaching than your regular mom and dad.
There are a lot of things concerning public education that homeschooling simply can't offer. Unless the public school in question is a festering cesspool of guns, drugs and violence and the child's health is seriously in danger, there isn't much that speaks for homeschooling. At some point, kids will have to go 'out there', and the sooner they learn how to deal with it, the better they will be prepared.
As much as I support public education, I disagree with most of your reasoning. Teachers have experience only if they are . . . experienced. The newer ones obviously have less. Formal teacher training is all but useless, except for practice teaching and good mentoring on the job. Mom and Dad may not be teachers, but they know the individual needs of their children better, and will give them much more individualized attention than a teacher with 20-30 in a class can. Mom and Dad are also not going to be distracted by disciplining class troublemakers or other school administrivia. Most homeschoolers do get "out there", in clubs, teams, learning co-ops, and other activities, so the socialization argument doesn't generally hold, as many here have already pointed out.
Some advantages of public education, at least when decently realized, are the consistency of subject matter offerings; the availability of resources, especially in the sciences, arts, and modern languages; exposure to different teachers/styles (as you mention); and "one stop shopping" for a variety of clubs, activies, and opportunities to interact. Homeschooling families often cobble much of this together rather successfully, but since they are already paying for it in their taxes, it is foolish not to make use of the resource and to reinvent the wheel instead. Depending on the reasons for homeschooling, it can also serve to insulate kids from people unlike themselves. By contrast, the greater diversity in a public school can be both a blessing and a curse, but on the whole, it is useful to encounter different perspectives, and learn to get along with people unlike yourself. There is also an efficiency in consolidating education in the hands of professionals, in a dedicated setting, allowing parents to pursue their own careers/professions and make their own contributions to the community.