The field has gotten much much bigger since then. There were so many foundational contributions to the field of computer science that we’re still recognizing th

The field has gotten much much bigger since then. There were so many foundational contributions to the field of computer science that we’re still recognizing them today. There are subfields within subfields of computer science that attract as many researchers as were in all of computer science fifty years ago (think about some of the ML subfields like graph neural networks or style transfer for great examples of this). This means that new researchers not only have a lot more to learn (and also bigger shoulders to stand on), but also that it’s a lot harder to make your research generally applicable across enough of the breadth of computer science. That’s not to say that the work that Knuth performed wasn’t worthy of the Turing award, but we’re in a world now where you could easily be 37 and only recently have been awarded tenure (if you’re even lucky enough for that), making him an outstanding exception.