I wonder how much of this is due to innovation happening "under the hood" rather than on the surface. As an example: the newest model of iPhone looks 99% the s

I wonder how much of this is due to innovation happening "under the hood" rather than on the surface. As an example: the newest model of iPhone looks 99% the same as the original one that came out 15-20 years ago. The iPhone 5 years from now will probably look the same. Compare that to the difference between cars in 1960 and 1980, or telephones in 1980 and 2000. The external form is vastly different.