That's true, but going for a faster commuting speed has little to do with the overall time of the commute. It's about the speed.

I had one of my shorter duration commutes today, cruising in the shade at around 14 mph. It took about 3 seconds to pull my bag out of my trunk pack, I didn't need to change or clean up, just straight to my desk.

I do like the advice about shaving time at the endpoints though, and I've gone to some trouble to do that myself. My handlebar bag (for the road bike) is aero and I can just pull it up and off in a quick motion, transforming to a backpack. Even quicker than messing with the trunk. But that's about saving time, not going fast.