The hippies failed? That would depend on your criteria. They didn't accomplish some of the specific goals that were pursued, but they did accomplish the broader ones. The hippy movement was born out of a general discontent with their parents' way of life and code of ethics. They sought to change people's thinking on whether conformity to the current standards and belief system is as essential as their parents believed or even desirable in every situation. That was the major goal of that time period, and they accomplished it. And that led to huge progress in civil rights, the women's movement, etc.
Obviously, some of the ways the hippie generation experimented with non-conformity were not successful, such as the drug use and free love. But then, fanatics and extreme actions are often used during periods when the masses seek to break free from ingrained schools of thought. Over time, the extremes die off due to implausibility, and a more reasonable compromise takes hold. That's where the real proof of success or failure lies - whether that ends in real improvement or not.
As far as the drug use goes, you have to remember that their parents' generation was very big on alcohol, and it was never acceptable to acknowledge alcohol problems, much less speak of them - one brushed such things under the rug. Papa wasn't drunk, he was "under the weather". The hippies traded the alcohol for drugs. But because their goal was to break free of their parents' strict set of values, they took the other extreme, which was to be extremely open about it.
And because they did bring it out into the open, the masses were suddenly and brutally exposed to the reality of addiction which had been kept mainly hidden until that point. And the result of THAT led to people finally being able to seek help, and educated people on the risks involved. While there are and always will be drug and alcohol addicts, there are fewer now than when it was all kept hush-hush, and there is now help available for both the addicts and their families. So that, too, had a beneficial affect on society in the long run.
What about free love? Do a little research. How many of your very own relatives back in the 50's and early 60's were pregnant when they got married? A startling proportion, actually. It was an acceptable (if quiet) practice for a woman to intentionally get pregnant in order to get her beau to marry her. And affairs while married have always been fairly commonplace. But again, these things were swept under the rug - even to those who were guilty of the same, it was considered highly socially unacceptable. Here again, hippies just decided to bring it out into the open, spurning what they felt was hypocrisy in their parents' generation. As a result, we know a lot more about STD's and how to guard against them, we've seen that polygamy tends not to work out well for most, and an unmarried pregnant woman (as well as the forthcoming child) no longer has to live with a strong stigma attached.
The hippies spawned the natural foods movement, which made people more aware of what they eat and how it can affect their health. That diluted and spread to the general populace, resulting in more research being done. We now know that eating a steady diet of food fried in lard and bacon fat is going to shorten our lifespan, for instance. In turn, that led to an awareness of fitness and the need for regular exercise. Daily life now generally requires less physical exertion than it used to, and so it's becoming increasingly more important to supplement it with planned activity for good health.
Freedom from strict conformity entailed questioning authority. Instead of accepting that our parents, the clergy, the government were always right, the hippies chose to think things through for themselves, speak openly about it, and attempt to change what they felt needed changed. While there were fanatics among them, and people now wouldn't necessarily agree with some of the individual opinions involved back then, the result is that it is far more acceptable now to form our own opinions rather than accept the commonly held beliefs, and to voice our that opinion even when it goes against authority or current standards. We now have far greater freedom of speech and laws to enforce that right. It is now more acceptable (and less risky) to go against the system in order to try to change what we believe needs changed. The hippies paved the way for that.
The hippies brought forth an awareness of ecology, how what we do to our environment in turn affects our lives and our health. That led to stricter laws on toxic waste and similar things. Whether you consider global warming to be of immediate concern or not, you can still appreciate laws against corporations polluting your drinking water with toxins, for instance.
I'd say the hippy movement was pretty successful in the long run.