"I've never understood the desire for beauty in a theory of everything."
It comes from the history of physics. A few equations define classical dynamics. Maxwell's four equations describe electromagnetism. A few short equations define quantum electrodynamics. High-energy physicists have been looking for something equally terse. It just isn't happening.
Once we properly understood it we realized Maxwell's equations could be reduced to one equation (the d'Alembert operator applied to the electromagnetic tensor gives 4-current scaled by a constant).
I'm sure whatever turns up for quantum gravity will be hideous to begin with, but then eventually we'll understand it.
It comes from the history of physics. A few equations define classical dynamics. Maxwell's four equations describe electromagnetism. A few short equations define quantum electrodynamics. High-energy physicists have been looking for something equally terse. It just isn't happening.