The things that make TeX and its offspring so sticky are: I agree with your list, but I think you overlooked another crucial one: TeX is one of the most remar

The things that make TeX and its offspring so sticky are: I agree with your list, but I think you overlooked another crucial one: TeX is one of the most remarkably bug-free and stable pieces of software ever written. For all its quirks, you can take a .tex file written for an academic paper 30 years ago, and you can run it through a modern TeX implementation today, and there's a good chance that your output will be identical for all practical purposes. Just about everything about TeX and its supporting infrastructure is rigorously specified, robustly implemented, and of course incredibly well documented. In the era of moving fast, breaking things and pretending it doesn't matter, many dev teams could learn a great deal from TeX's priorities. Given the momentum behind the TeX world now, I suspect that anyone who wants to offer a more modern alternative is going to have to clear that bar as well (and I hope this project does, because it seems to have a lot going for it in other respects).