Complex closed systems are susceptible to cascading failures, infectious outbreaks would be one possibility to begin such a cascade. Or imagine a minor HVAC issue: a small build up of moisture. If not caught right away, it leads to mold, possibly "sick building" syndrome, stresses medical resources, moisture damage to structures, etc. Structural damage harms other resources, takes them off line, and more humans are needed to fix those problems, in and on.
Sure, you have things like that with buildings now. But they're not closed systems: You have problems like the above, you ramp up resources dedicated to the problem, bring in outside help to remediate, etc.
I think the higher the desired quality of life, the larger a closed system would need to be. Think a few hundred years ago: a small village could be self sufficient. The average town in Western society cannot be. Even a farm town, with it's reliance on heavy machinery and agricultural industrial complex, isn't self sufficient.
Sure, you have things like that with buildings now. But they're not closed systems: You have problems like the above, you ramp up resources dedicated to the problem, bring in outside help to remediate, etc.
I think the higher the desired quality of life, the larger a closed system would need to be. Think a few hundred years ago: a small village could be self sufficient. The average town in Western society cannot be. Even a farm town, with it's reliance on heavy machinery and agricultural industrial complex, isn't self sufficient.