Biggest impact I've found which is not directly discussed in the OP: A great package repository (e.g. CPAN) can outweigh quirks in language design (e.g. Perl spaghetti code).
It seems to me that TeX did the best job of winning at both -- over three decades, at that!
It seems to me that TeX did the best job of winning at both -- over three decades, at that!