@psu_13 @ColinTheMathmo TeX has been the unrivalled standard in the mathematical sciences for over 40 years because it is the most robust programming environment that I have ever used.
Yes, it contains throw-backs to 8-bit 1980s programming and it makes arithmetic and ordinary programming gratuituously awkward, but Knuth's insistence that it can only be changed to fix bugs is the reason for its robustness.
I didn't say LaTeX. In the early 1990s a bunch of Germans added some great code for selecting fonts to LaTeX. I wish they had left it there. But 30 years later they're still messing around with it and it's still called LaTeX2e, e being epsilon for "a small change".
For example, my commutative diagrams package was written c1990 with the policy that it works with plain TeX but *cooperates* with LaTeX if it's there (which of course it usually is). It relies on TeX's paragraph builder because that is the only way of splitting maths formulae. In no other programming environment would such a hack have continued to work for very long. But a few years ago the LaTeX-meddlers broke the paragraph builder and hence my diagrams. However, I managed to un-break what they did.
One day TeX will be replaced. May that day be postponed as long as possible! The "replacement" will be some bloated garbage from MicroSoft or Adobe that is full of security holes and stops working after a couple of years, to make you "upgrade" it to something more bloated and even more insecure.