Socialism is the single greatest advance in human civilization as a whole. Socialism is what has prevented all of the other great advances of civilization to be claimed, owned, and guarded by a powerful few.
And democracy is what enabled socialism. Without the advance of democracy in its many forms,
the economically/socially less powerful would have never gained sufficient political power to be able to wrest away from the wealthy the natural political power that accrues to wealth itself.
You left out the part about it failing every time it is tried.