[dubya]

"TL is big because it includes everything possible" isn't the confusing part, what's confusing is why it has doubled in size every couple of years. Is that all from CTAN? The other why could be: why do they include everything when they have a perfectly good package manager? I don't know if TL will do on-demand loading, but MikTeX on Windows did so years ago, so it should be possible.

[dfc]

The documentation for the different languages is huge. Plus all of the architectures. When I install I only install english/linux-x86-64 and its not that big. Plus fonts do not compress that well..