Presented with wholly inadequate logical explanation - that is, none.

• Hierarchy is the wrong abstraction. Layout and placement is a data flow incorporating more variables than simple positions and sizes, and as such are better modelled by pipelines such as reactive graphs.
• Placement of UI elements can be informed by layouts, but cannot be prescribed by them. That is to say, all placement is absolute positioning which calculates and factors in layout information at its own discretion.
• Layout is not prescribed to UI elements. There is, by definition, no single way to lay out a UI element, because the placement process may choose to generate whichever layouts it pleases in accordance with the current condition of the reactive graph.

Further hypotheses derived from these;

• Today’s layout systems are backwards. We have gotten very good at building prescriptive single-layout systems that wholly dictate placement.
• As a result, it’s obscenely difficult to blend between multiple layouts, or to ignore layout information. Anyone who has implemented parallax, drag & drop, or connected animations, has already encountered this friction.
• The first person to get the DX right, in accordance with the first three hypotheses, will enjoy massive success in unifying all placement processing into a universal, understandable, intuitive and debuggable pipeline.