I guess that's because in the UK "It's The Sun Wot Won It".[0] Summary: It is believed some media, like The Sun, have a big effect on elections' results, like with the recent Brexit referendum. This led some people to believe it's pretty much impossible to win against sensationalist media in the UK. (But please correct me if I'm wrong, that's my take after living in London for around 6 years.) And so Trump can be thought of as a surprise given his victory against the overall media landscape.