Why don't front end engineers report to back end engineers? It would seem logical since the backend teams are where all the magic happens and frontend teams ar

Why don't front end engineers report to back end engineers? It would seem logical since the backend teams are where all the magic happens and frontend teams are responsible for input and output. Conway's Law (https://en.m.wikipedia.org/wiki/Conway%27s_law https://en.m.wikipedia.org/wiki/Conway%27s_law) may explain why there are multiple teams, but it does not explain which team should be diving the design.