Until hard-drive manufacturers started trying to deceptively market smaller drives with larger sounding base-ten capacities, everything in computer-land was base-2 and things were simple. Now I can't fully trust any number put before me without digging into the specs. How is this a step forwards?
Let's draw a parallel with physics. Draw an electrical circuit. The current is measured to be traveling to the right on a wire. Which way are the electrons going? Left. When current was discovered, it was assumed charge carriers were positive. They turned out to be negative (most of the time). That was a mistake, but did we fix it? Nope. It would have caused far more confusion than it was worth. If physics can stick with current flowing the wrong way for centuries for the sake of consistency, we can stick with base 2 hard drive capacities.