I have troubled finding exemples in history where we made the "right" decisions for the future of humanity when we wanted too. Think religion oppression, communism, etc. Why today will be different?
The problem is when experiments continue despite failure.
Also - you should know there were communities without property before the Soviet Union.
And after. Arguably the problem with Communism isn't so much that it is entirely impossible, but that it is entirely possible for it to scale much past 50-100 people, making it an exceedingly poor choice to try to structure a country's governance with. (And generally even by the 50 person mark the strains are seriously setting in and the community frequently still becomes unstable and disintegrates.)
But I get your point, just substitute any of the human catastrophes of the nineteenth century.
Well, thats kind of unsurprising, since all the actual attempts to implement “Communism” on a national scale threw out the prerequisites in Marxism on favor of the (notionally transitional) elite ruling class of Leninist vanguardism (an adaptation to allow bypassing capitalist democracy entirely, because—viewed generously—the Bolsheviks and their successors were too impatient for Marxism.)
There is a reason why slavery was abolished on the brink of capitalism birth. It's because capitalism depends on free trade, not just any kind of it - the freer the better it grows.
*freedom for the property owner. Which is why it can facilitate a slave trade, property is a limitation of freedom.
By the same token, you could argue that Nazi Germany was an "absolutely worthwhile" experiment. "Hey, societies with mixed race have all sorts of problems, let's see what happends when we change that variable!"
Some ideas are simply WRONG when you try to apply them in practice.
(I don't know you, so maybe you've also experienced communism and totalitarianism first-hand; but if not, I would respectfully argue that it's easy to judge something as "worthwhile" if you haven't personally been affected by it.)