The problem is that to get anything done on the Internet, you will need easy use of existing third-party libraries for a wide range of stuff, or you end up spending huge amounts of time implementing protobuf handling, websockets, ajax, webgl and the myriad of other important technologies that you may likely encounter in those areas. Excellent libraries for that stuff are out there, but Elm makes it hard to interop with them... for now. I really hope that changes.