?? Centuries? You mean twenty/thirty years, probably? We don't really have computers until about 50 years ago, and even then it was not widespread.

You don't have to wonder what post-Moore's law will look like. Look at other industries when they become mature. The car industry is one example: there's not that much innovation that goes into making a car better in terms of performance. I mean, a car from 30 years ago may be less comfortable but still drives pretty well as long as it's maintained. What makes the difference then is not performance anymore but whatever added value you bring on it: durability, reliability, service, etc... no doubt sooner or later electronics makers will have to innovate in different directions as well.