The problem isn't that the original codebase is messy (it's aged, but there are still comparatively new projects working on it e.g. LuaTeX) or that it's non-por

The problem isn't that the original codebase is messy (it's aged, but there are still comparatively new projects working on it e.g. LuaTeX) or that it's non-portable, as demonstrated by the multitude of platforms it's available for. The problem is roughly equivalent to producing a non-upgradable perl. It's not very useful on its own, but it's completely impractical to include a copy of the entire CPAN with it. And Apple's policies prevent you from downloading additional packages. It's just not worth the effort.