Yea - from our experience in "living together" it's taught us a lot. It's NOT easy - at times next to impossible. There's something very intrinsic to human nature to need our "own space". Bringing too many people together in close quarters violates that and usually ends up causing problems where - as you suggested - there maybe should not have been.
We learned that early on from participation in communal living - and not even in poly loving situations.
On the other hand there CAN be many benefits to living closely with other like minded people but our basic natures need to be acknowledged.
You may be aware of a maturing philosophy that is becoming more & more common these days. It seems especially more so in Europe than here in the states. It's most commonly referred to as "Intentional Community(s)". It's a model built from some of the hard early lessons of "communes" etc. They are usually built (membership) around some central set of ideas, principals etc. I can see not better application than polyamory for such communities.
They often take pages from organizations similar to condo associations in that there is some central "governing" organization that helps run some of the bureaucratic necessities that are desired. These may range from communal meals, food coops, assistance with maintenance & upkeep of central facilities (communal kitchen, recreation areas, school facilities etc). But the all important need for "private space" is a key element. Each individual or maybe couple has their own place they can retreat to for solitude when desired.
I can see where a similar philosophy could work if a smaller group just had a BIG house. Multiple bathrooms, media rooms, kitchens etc.
We'd had live-in triads for example and some of the silly stuff that comes up that causes REAL strains is amazing. Different sleeping patterns/preferences. Media preferences (music/movies etc), hair in the bathroom sink. Silly stuff but important. K will say that a lot of these things are a much touchier subject with the women than the men. Minor differences between the definition of "clean" can be all it takes ! <chuckle>.
Yeppers - been there - done that. We've said "never again" unless we get a mansion or were to find the right "Intentional Community" to join with heavy emphasis on private space.
If you haven't run across this before check it out ! Lots of potential there. We think it may be the "future" of how most people live - for practical/ecological etc reasons. Poly would just make it that much more.