You're right; tree-shaking doesn't eliminate all instances of dependency bloat. Come to think of it, I've even seen a counter-example in C++. On Windows, a hello-world application using the wxWidgets GUI toolkit is ~2.4 MB, even statically linked. I think the problem, or at least part of it, is that the WindowProc implementation uses a big switch statement to handle all of the Win32 window messages that wx supports. So, for example, the handler for the WM_PRINTCLIENT message has to be included even if your application doesn't do any printing. Same for drag and drop. It would be better if the WindowProc implementation looked up message handlers in a table, and the application could ask wx to register the handlers for just the features that are actually used. I wouldn't be surprised if similar concerns apply to frameworks like Angular, even in Dart.