To be honest, I don't think the DOM structure itself is what consumes the most memory. It's about priorities, and having the UI building blocks be a bit slower

To be honest, I don't think the DOM structure itself is what consumes the most memory. It's about priorities, and having the UI building blocks be a bit slower is probably fine, because the actual UI internals will still be fast. How many times do you need to reflow your UI? Though I'm not super aware of what Cocoa actually covers, my impression is that it's mainly UI libraries.