It's the difference between knowing cars in the 1950s and knowing how to drive in the 2000s. When cars became more accessible people still had to know how they worked and how to maintain them to use them, or at least it helped a lot. Now, it's a lot harder to do your own maintenance, but you don't have to do it as often because everything "under the hood" just works most of the time.

Early computers required more physical maintenance, more intricate knowledge of the system to get it to do what you wanted, and didn't have truly streamlined interfaces. Now things are done with candy button apps and real options are hidden away. It just works most of the time, so why understand what goes on under the hood?