Native speakers of English, could you help me with English paragraph?

I am translating a paragraph and since I'm not a native speaker of English I find some phrases difficult to understand. Does the phrase 'together with the institutions which they once embodied' mean that the below mentioned void was left by those institution or does it mean that the void was left because of our incapacity to realize clearly defined urban domans AND to realize clearly defined institutions they once embodied?)

The void left by our incapacity to realize clearly defined urban domains, together with the institutions which they once embodied, was hidden until relatively recently by the optimistic illusions of operational planning, a quasi-positivistic discipline whose effectiveness in managing the consumer economy was contingent upon maintaining a certain indifference towards cultural form.