Making the association that an anarchist is the same as a libertarian is a leap and a half. In my mind its like calling a Republican a Liberal. As for socialism, can you give me your ideas on why it has failed every time its been in place?
I dont know if it was this thread that I mentioned the how libertarian the word entered into modern American parliance, it was originally a word which was synomyous with anarchist, not just in French but mainly in French, were some thinkers like Daniel Cohn-Bendit (who's a social democrat now) argued that anarchism/libertarianism was synomyous with socialism, there's a good chance it was originally.
The differences I can fully appreciate, most libertarians are minarchists, even if they do believe in eventual privatisation of all functions. In fact that is one of my reasons for critically opposing libertarianism, in the main, by design or default, it will not remedy problems or dispense with oppression but will merely privatise them. I have met some "honest" libertarians, pretty mean guys, who are fine with that, they'll work for the highest bidder and wont split hairs about whether they are a tyrant or not, some of them would consider being paid to oppress others or intimidate or kill people challenging oppression to be a positive plus.
On the other side of the fence, so called "left libertarians" or those who I think are sincere about being "beyond left and right", there is too much sympathy for, or at the very least complicity with things like the ousting of Mozilla/Firefox's business leader for privat opinions which had nothing to do with his actual work performance. I dont want to live in a society which is some rough reflection of a stereotypical eighties American highschool at its worst/best.
Why has socialism failed? Hmm, I would have to think about each and every instance, there has been as much diversity when it comes to socialism as there is in capitalism, although I know that libertarians are inclined to look upon mixed economies, public planning, competition policies, nationalisation and proper controls of financial sectors to all be betrayals of capitalism, so perhaps the Rhineland and Scandinavian versions of capitalism, wrongly labelled socialism (although I tend to think that anything US conservatives dislike is labelled socialism these days), wouldnt be considered capitalist at all.
I consider democratic socialism of the sort supported by British socialist GDH Cole or supported by Erich Fromm in The Sane Society to have been a success where or when it has existed, which is usually on a very small scale and in a temporary, time limited fashion, as I've posted elsewhere I also think that the ideas of Henry George, asset based welfare systems and basic incomes are all steps in the direction of the sort of socialist society I believe is most attuned to human nature and consequently liable to satisfy human needs that capitalism does not (even in its best case scenario, I'm not a fan of comparing socialism at its best with capitalism at its worst or vice versa, there's no perfect societies, just those that reflect more or less one ideology or another but reflecting more than either the prevailing class struggles and social struggles).
If that helps, I dont believe that socialism and capitalism are zero sum games, I dont believe that one succeeds and the other fails and its a done deal, dustbin of history etc. If I'm really honest I believe that there are many, many things trending at the moment which make neither capitalism, nor socialism possible but that's a different story maybe.