I'd like to add that I don't think that all group learning environments are inherently bad. There are lots of things I've learned in group settings, even school!
My point is that it's up to each person in the audience to try and make the information stick in their brains. If they are unwilling or unable, no amount of fabulous teaching is going to make it happen.
I do feel for teachers who are trying to engage the attention of 25 or 30 kids all at once and how stressed they must feel when they realize that only some of the knowledge they are trying to impart is being received by only some of the kids.
I can't help but make a business analogy. Imagine a Coke factory. Thousands of empty bottles zipping along a production line. They get filled up with soda, capped, and are sent out the door. Schools and school systems want to be Education Factories. The empty children are filled up with knowledge, capped and gowned, and sent off into the Real World. That is the primary intent, anyway.
The big difference here is that Coke bottles don't need to consent to the production process in order for a finished product to be achieved. They don't resist being forced along a certain path to the finish line. They are identical in size, shape and function. All of these factors are conducive to efficient mass production (which I'm generally in favor of--it was my favorite field of study in business school and specialty in the business world).
To state the obvious, children aren't soda bottles or widgets or any other sort of production input. Mass production of education is impossible due to the uniqueness of each child. Although similar in size and shape, their brains need and desire different kinds of knowledge. One kid may need art-y things. One kid needs math-y things. One can't get enough of bugs. Consider the fact that each child needs to know different things at different times (in different ways), multiply by 25 kids, and the complexity level of "teaching" effectively (let alone efficiently) quickly rivals other chaos theory problems such as meteorology.
The answer here is not just smaller class sizes. It's allowing the learner the freedom to discover what he needs to know and to learn it in his own fashion in his own time.
Still more to come as I consider what I've just written. Feel free to comment!