Creature features aren’t just movies starring a monster, they were the hosted or non hosted block of films broadcasted on television around the 70s and 80s They relied on films mostly from the 70s and before: Hammer horror movies, Japanese monster movies, 50s monster and alien films.

What killed then was horrors increasing reliance on gore, I think. Also sort of the camp aspects of genre films and their transition into serious business.

While Syfy films tried, they were too low budget and not particularly likeable.