What Gibson is saying is that, (1) The rate of development of new technology is speeding up and that, therefore, (2) Humans experience an increasing amount of change in their lifetimes.
So, in a way, the future is getting here quicker.
As an aside, I can't wait to read his new book. I got it when it came out and promised myself I'll save it as a luxury to read in between getting my startups product ready to launch and actually launching. I've had to cellotape it back in the Amazon box to ensure I stick to my promise.