I think Psycho has to do more with the competition in that genre at that time. It is considered the seminal slasher film and with Hitchcock it was well received before anyone saw it.
At the time, it affected shower curtain sales like nothing ever had before and he was excellent at showing you just enough and using black and white for the shower scene had this strange quality to it at the time.
I liken Psycho to Alien, until that came out, there was this opening just waiting to be filled by something we hadn't seen before. Then it had too many films following and imitating. I watched Psycho when I was 13 and there was nothing like it, no Jason, Michael or Freddy with the blood and gore.
But those slashers can't hold a candle to the guy in Wolf Creek for me. There is a scene in that film that stayed with me well beyond when I first watched it.