Or, it could be that TeX has been cobbled together over decades with little design guidance or vision, resulting in a mishmash of approaches and inefficient code.
To me almost everything in TeX feels like a hack, even if the fundamental idea is good and the sum of all hacks ends up looking pretty good. The fact that it's a huge hack that takes 1.3GBs to install is not a gauge of quality.
It only takes 1.3 GB if you install every package ever invented. A normal installation of TeX Live takes about 200 MB and includes all the binaries (including tex, pdftex, xetex and luatex), a full LaTeX and ConTeXt and a whole bunch of other libraries.
I usually just install that, and then tlmgr any missing packages instead of downloading a gigabyte of TeX code I'll never need.
The full TeXLive is 1.3GB large, because it ensures that the only thing you need to build any semi-sane TeX document is this installation.
Describing TeX as Code misses the topic by a wide margin, a lot of the things in the distribution are fonts and compiled versions of the documentation.
Bash the idea of treating TeX as code out of your head and you will find it quite a bit saner.
To me almost everything in TeX feels like a hack, even if the fundamental idea is good and the sum of all hacks ends up looking pretty good. The fact that it's a huge hack that takes 1.3GBs to install is not a gauge of quality.