This also applies to operating systems. After that, further releases will merely be refinements. Operating systems will be a mature technology. From time to time new genres of software are introduced. Browsers were only introduced a few years ago, and are not yet mature.
Search engines are still very primitive.
We can look forward to dramatic improvements in the next few years. But after a while, search engines will also be a mature technology, and further releases will bring only asymptotic improvements. Improvements in software are not exponential. In hardware, one starts with the idea of a circuit, and then one implements this idea on successively smaller and faster substrates. Software doesn't work like that at all.