Ooh, we are talking about appartments, not houses ! Makes more sense.
I'm not from the US and I thought the HOA were only these evil organization that control the color of your paint and the height of your lawn, paying that much for these felt very wrong. In the context of an appartment building it's different (although still super expensive !).
They are the same. The HOAs exist to maintain the housing and its market value. You are not paying them to act as hall monitors. That is a by product. You are paying them to fix things when they break.
With shared ownership models, you typically pay into a shared pool that can be drawn from to pay for maintenance needs.