I'm talking about upstart games, movies, TV shows, cartoons, etc. that introduced themselves to the world by immediately claiming how they were the next big thing, typically by calling out established names in their given genre and insinuating how much better they were... and then completely failing to set the world on fire, either through plain badness or just being unremarkable.

"Thicke of the Night". Was promoted not only as the show that would knock Carson off his throne, but as a game changing TV show. The producers quickly learned the lesson so many other found out; don't take Carson head on.
"Space 1999". A big money sci-fi show the American networks didn't want, but many affiliates pre-empted network offerings for it. When viewers found out it was just another space opera, lasted barely two seasons.

How about the Chevy Chase Show and New Coke?