physically? That's the point. you don't get "pure capitalism" or "pure comunism". But abstractly, and relevant, physically:
For communism, or public ownership of production (and often, resources in general), the issue is that it is easily hacked by individuals who seek personal advantage by seizing control of the distribution of assets - but the system relies on people not doing that. this occurs both in the large and small scales. on the kindest end, this looks like "the fireman's ball".
For capitalism, or the private ownership of production (and often, resources in general), the issue is that it's sustainability depends on "enlightened" or at least reasonable self-interest, but winning strategies often don't have those characteristics. In effect, when no public-sector oversight is present, capitalistic systems shit the bed. when public-sector oversight is present, capitalistic systems tend to remove it.
Feel free to disagree about any of this, but I don't think I'll be pursuing this conversation further. I don't think it's likely to be fruitful.
living out in the woods, getting dirt on your hands, and learning to work well with feelings again.