From www.screenrant.com:
"Horror movies appeal to the human perversity of finding pleasure in being scared, and it's this reason why the genre captures the attention of such a wide audience. Today viewers are accustomed to CGI monsters and jump-scares, much to the genre's detriment. But, when horror movies were ascending into the mainstream during the 1970s, they were made on lean budgets that couldn't afford the cheap scares of today.
Let's not be unfairly harsh on current horror movie trends, since these early films were the pioneers of the special effects that now dominate much of the genre. The lack of special effects as the result of insufficient technology and small budgets also meant that these films had to use other means to be scary. They use the power of gore, risque content, dreams, atmosphere, among others to create the desired frightening effect."
