Each more complex theory turns into its simpler predecessors jn certain cases. There’s no magic in that, it’s simple math: if v << c, then the equations of spec

Each more complex theory turns into its simpler predecessors jn certain cases. There’s no magic in that, it’s simple math: if v << c, then the equations of special reativity become much easier and we get Newton mechanics. The same applies to the rest. If you want to discuss why does our world have to obey the math — that’s a whole another story.