Griffin wrote an AIAA textbook on spacecraft design.
And yet still managed to run the Constellation program into the ground.
I'll say it again. a hugely overpriced HLV launch cannot compare to MLV's that cost a small fraction. Even with your version of depots being "leaky" and
the added complications of assemble in orbit MLV's are still the best way to go. The price gap is just to large. SLS will cost billions to launch. How many F9's could you launch for the price? how much payload tonnage? Do the math. It doesn't lie.
I'll give you this. The one time a HLV has an advantage over multiple MLV's is when you have a payload that cannot be broken down into parts. Like a huge single mirror telescope. But you will pay out huge for that.