You clearly don't know how complicated a music player + music store + music library manager can get. There's a bunch of stuff going on there between music codecs, library management, streaming music downloads, pulling id3/etc tags down from db servers, copying music to mobile devices, managing playlists...

I've written game delivery systems which were smaller, like 1/20th of the size.

You aren't exactly going to be writing the CODECs and DRM for XBox Music in TypeScript are you?