As someone who spends a lot of time among horror filmmakers and fans, I'd say you are very, very wrong. Horror comedy has emerged as a defined subgenre, but it is by no means the "only" one.
No denying each franchise got increasingly campy, and that FvJ played that up in moments. But if you're saying we can't get scariness out of either character, you're displaying ignorance - Camp Blood and Dreamwalkers were apparently terrifying in 2007. Saying we can't expect a similar level of intensity in the "Crystal Lake" and "Boiler Room" sequences is inaccurate.