When comparing any of Hitchcock's horror/murder-thriller to any more modern horror, such as Disturbia, one must remember that back in the 50s and 60s when Rear Window and Psycho arrived on the cinema screens this was the first encounter for many of the horror genre to such an extent that can be found within these, whereas in modern times something as fear inducing as the Bates serial killer can likely be found on any soap opera.
So for people back in the 50s and 60s films, like Psycho, were terrifying, whereas something like that has no effect and is almost normal for any media text to include, and so some may see Disturbia as less of a movie because it just isn't scary enough. However this does not make it less of a horror film, but simply the fact that it is a more soft-core version of the genre, as opposed to hard-core titles like the Hostel or Saw franchises which are seen as more scary due to the fact that they fit into the realm of torture porn, which would never have made it through pre-production stage back when Hitchcock was fighting for the rights to take Psycho from book form to a feature length film.
The difference in time is also the reason why people refuse to watch old films such as those of Hitchcock, purely because they are either in black and white or because they think the visual effects do not look good enough, and this couldn't have been helped because of the lack of special effects and less advanced technology. Admittedly Psycho was filmed years after Hitchcock had began to film in colour, however this was for effect and the ability to use syrup as blood without the audience knowing any different. The only benefit of this is that modern directors take these ideas from older films, such as D.J. Caruso with the adaptation of Rear Window, which leads to people who enjoyed the new film to go back and revisit the original, and so a whole new group of people have their minds opened up to the classic horror genre, meaning that these older films will always keep their relevance within the film industry.
