Ha, I agree most of his books evoke having been written during stimulant binges; rich and detailed world building in the beginnings transition to incoherent plot driven action at the endings
I enjoyed snow crash probably up until 2/3rds through, same with cryptonomicon. I truly wish he would stick a god damn landing. I don't know what happens after the halfway marks. It's like a different writer takes over and it jumps the shark. I stopped reading his books after a while when they all seem to go off the rails. Damn shame really.
Diamond Age is the most important science fiction book of all time... until you get to 2/3 of the way through and the guy in the ... underwater? hippy? drug dream? It never recovers.