It describes the very low level of a program and a computer.
No it doesn't. It describes the very low level of a program running on a computer from 30-50 years ago. The lessons that it teaches about algorithmic complexity are still valid, but the low-level stuff is not. Once you get to limits of the implementation, rather than of the algorithm, artefacts of caches in pipelines are far more important to performance. Not only will you not find, for example, Hopscotch Hash Tables in TAOCP, you also won't find an explanation of the underlying reasons for their performance.