But it's not "just" a typesetting program. The TeXlive installation includes a huge amount of packages, supporting all kinds of typesetting, including maths, music sheets, pictures (TikZ), support for making posters, presentations, various little enhancements like microtype etc. etc.

I am quite happy to dedicate 1GB to that. Especially in a world, where random websites tend to dump 3-4MB on me (with liberal use of adblockers) to render a few paragraphs of text.