Casey's complaint is basicly that there are several million lines of code between an application and the hardware. This creates a large problem surface i.e. performance/security/complexity. In addition, the current hardware is so complex that an software/os (r)evolution is not possible. Casey suggests an SoC+ISA and vastly simplified interfaces for SATA/USB/NICs/etc. Which would make it feasible to ship custom OSes with just a few 10 thousands lines of ASM/code. Downside is that this would require interest from chip/hardware vendors.
--
I lack technical depths regarding hardware and OSes, but I like that idea very much. Shrinking the OS parts to comprehensible sizes would vastly change the landscape. Programming computers would be so much more interesting if a single individual could grasp all of it.