Oddly, I would cite Knuth's rigor in stability as much as in rigor of algorithm choice and creation. Specifically, TeX still works well today because of delibe

Oddly, I would cite Knuth's rigor in stability as much as in rigor of algorithm choice and creation. Specifically, TeX still works well today because of deliberate choices to not break things. He is well aware of modern techniques for many of the things that people complain about. He likes that he can still build every one of his documents today, with no concerns over things having "moved on to better ways."