You can't read game files faster because the process that reads the game file is single threaded vs multi-threaded... so it can only read as fast as a single thread can read.
A fully saturated CPU has enough lanes to do about 26-28GB/sec, but a single I/O thread might only be able to do 100-200MB/sec.
There was never any reason in the OS before today to make that any faster because the spinning disks that fed data to the CPUs couldn't do more than 100MB/sec.
Now that we have all this great flash, code needs to be re-written to be able to use other idle CPU time to spin up more threads and read the data faster.