In fairness, plenty of open world games have demos. The Yakuza series has had demos for all major releases, which were basically the world map with no story progressing or maybe one major event, with all the shops being accessible as well as random battle encounters. But saying that there's no point in getting a game without being able to try it first is laughable indeed... even on the mainstream market, games that have demos are becoming less and less frequent. Most people judge whether they like a game based on prerelease trailers or gameplay footage, or preview articles. And this game definitely has enough of both kinds of information floating around to make an informed judgement.