But the difference is the old stars actually made a living and specialised in these films, often turning in nuanced performances and raising a cheesy horror above it's worth and turning it into something classy.
Peter Cushing for example always gave a good performance even in a really shite film.
When a big film star turns up in a horror these days it often lessens the impact because the filmmakers are pandering to a big name, toning down the horror aspect and their performances are often restrained as to not ruin their star power.
Old stars made it their business, and business was good.
I agree it is good to have no name stars in horror generally as we are not expecting anything, it puts us on edge slightly and surprises us when a good performance appears especially in low budget horror like Texas chainsaw massacre etc. It makes a story seem more real when it works.
But a few competent new horror stars would be nice.
Too many horror films these days have sub par porn style actors that make the films unwatchable to me.
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MIKE: I've got it! Peter Cushing! We've got to drive a stake through his heart!
VYVYAN: Great! I'll get the car!
NEIL: I'll get a cushion.