Dart was never marketed (to my knowledge) as a general-purpose programming language. Go was marketed as the best thing since sliced bread, and especially as a "systems language", which it definitely isn't. It was also gaining popularity on HN at the same time Rust was gaining its initial wave of popularity (~2016-2017, around when I started reading HN), so the two were compared and written about a lot in a way that Dart never had the chance to since it never had a narrative foil.