They work best and are most resilient as networks of smaller farms, co-ops, and communities.
Anyone saying they can't last or support the elderly is ignoring the Amish(among others, but I went with the the first too-big-to-ignore and surviving example that came to mind), and so long as they can support and raise children and young adults, they pass muster vs historical societies in ways that un-bridled capitalism flat-out doesn't. Same goes for the length of time a given commune lasts - individual farms and villages that last centuries without moving or significant change were far from the rule throughout history and pre-history.
You need semi-independent artisans and experts at the periphery(well, between individual communes, and able to form external/transactional/distant trade/relationships) as an interface and buffer, and even seasonal assistance for things like harvests - scale requires diversification and organic trade/distribution - but for some reason popular imagination all-but-stops at stalinism/maoism vs individual farms.
The whole notion that its a pipe-dream if it can't scale the same at all levels and from one end of the earth to the other is an unreasonable goalpost used to justify power grabs and the status quo.