The whole "let me put TAOCP on pause while I create TeX just to create it properly" story always fills me with awe.
I'm also incredibly grateful --- I was gifted a NeXT Cube by my brother-in-law when I was in college studying graphic design, and I was incredibly put out by the paucity of nice typography features in Quark XPress and Aldus Pagemaker when I came across TeXview.app and remembered checking out the book _TeX and Metafont_ from the local college library when I was a senior in high school --- built that into a career and a series of presentations at TUG conferences where I got to meet him.
See the "future plans" section of his website: https://www-cs-faculty.stanford.edu/~knuth/taocp.html has volumes 6 and 7 as being on compilers.