I have no problem with stories like this making it to the big screen. Like many movies, there is some degree of "escaping from reality" that many people desire to see and following a story full of winners makes everybody happy when they leave the theater. There is a place in the spectrum of films for stories like this; dozens more have been made and will be made where the down and out are helped to success by caring outsiders. School teachers tend to be featured in such films.
All that said, I do have a nit to pick with this movie because it implies that the problem that many of the "under-privileged" have is a lack of opportunity, that nobody seems to care enough to give them a shot. These films tend to portray a situation where the key to changing lives is that loving mentors give these children the opportunity to succeed and they will. In this film, the family that takes on the down-and-out youth does invest quite a bit; they provide him a home, clothes, food, a tutor, and genuinely make him a part of the family. Based on my relatively limited experience with working with at-risk kids, I'd have to say that the story ordinarily isn't as simple as that. Often, even when given opportunities, kids in the these situations do not respond well and often end up making choices that are self-defeating. More simply put, coming from a broken home can't be fixed by a change in circumstances, at least for most people.
Most kids who have difficult home lives have more than problems than the externalities of these situations; its more than not having, say, a reliable source of food, money for school supplies, a quiet place to do homework, parents to offer support and encouragement, etc. These are all real barriers and some of them can be overcome simply; the federal school lunch program is an example of such an attempt. More fundamentally, though, these students have a problem with developing good decision-making skills and behavior patterns that will allow them to grow into healthy, mature adults. You might call this "having character", in a non-moral sense of the word.
The cause for this lack of character development is usually straight-forward: the naturally influential adult figures in their lives (mostly parents) often have not been good role models and have failed to instill these good habits to their children, usually because they don't have the habits themselves. The damage done to these students has been deeper than a school-lunch program or after-school tutoring can fix. It requires digging in and making a significant investment of time and energy. It requires a great inconvenience on the part of those seeking to help and, in my experience, will be more frustrating than rewarding for a very long time.
The church I attend is partnered with an organization called Youth Horizons that seeks to provide mentors/role-models for kids who are in these kinds of difficult situations. I have many friends who are mentors and know a few of the stuff there decently well. For all of them, it is a labor of love. There is no high-altitude "love-bombing", this is "in the trenches" kind of work that isn't done in a casual way. The only reason they stick with it is that it can sincerely believe that this kind of work can actually change lives and have meaningful impact down the road.
I had a friend from my time in Boise that, in his thirties, finally was reaping the benefits of investment that others made in his teenage years. Fifteen years after his time in a church youth group where he had many loving adults pouring into his life, he realized that his life back then was better than it was now and that he needed help like that to get his life in order now. He moved back Boise, where his old youth pastor was working, still in ministry, and asked for help.
I ended up connected with him and saw a humble man who had realized that many of his choices in life had not played out the way he hoped and that he needed a fresh start under the influence of people who cared about him. There were some externalities that needed fixing: he needed a cheap place to stay, he needed a job, he needed help getting his finances in order. More importantly, though, he realized that he needed a new character. He needed to learn how to make good decisions for himself, he needed to learn how to make short-term sacrifices for long-term gain, he needed to learn how to follow-through on commitments he made. He was extremely teachable and a joy to walk along side as he tried to re-build his life and it was all because of the investment made when he was a young adult.
Clearly, children who don't develop character in their youth grow up into adults that also lack this kind of character. Being ten or twenty years older than a teenager does not guarantee character; an individual has to choose to learn and grow from experiences in life to gain that character. Without that character, they lack the ability to raise their kids in a more successful way than they know. You can't instill a value in your children that you yourself don't have. When people talk about the problems coming from broken families, in my mind, this is the fundamental issue, this cycle where a lack of character continues to perpetuate itself from one generation to the next. We all "inherit" the failings of our parents; they are the most influential models we have and whether we like it or not, we bear their fingerprints on our lives.
I hope that movies like "The Blind Side" inspire people to be more involved in their communities, helping students who have rough backgrounds to grow into men and women of character. Steel yourself, though, because it probably won't be as easy as what you see in the movies. Count the cost and make the investment.