TV shows that were the next big thing but weren't?

I don't keep up enough with television these days to even know what any of them might be.

Supertrain was before my time but I believe that fits the description.

I thought that Dinosaurs could be an example. I just looked it up and I was surprised that it had four seasons. I think in my country it had a big build up but then disappointed and was quickly taken off prime time.

Viva Laughlin was a Hugh Jackman musical drama that didn’t last.

Then there’s The Chevy Chase Show. I watched a vid about that recently.

I completely forgot about the Bionic Woman reboot.

That actually had a lot of viewers over here, and an extensive advertising campaign in the leadup to the show's airing.
As for the show itself... to say that the title character was miscast was a massive understatement. Many have said that Katee Sackhoff, who played the show's antagonist, should have been made Bionic Woman instead. Constant changes in the production team left the show lurching from one direction to another, and then the Writer's Guild strike of '07-'08 brought an end to the show after just eight episodes.

I tried watching it, and gave up after barely two episodes. Probably not a good idea to cast a relatively unknown actor/actress as the protagonist when the antagonist is played by someone better known and more experienced at acting. (Katee Sackhoff had been in Battlestar Galactica, The Education of Max Bickford and Halloween: Resurrection by that point, whereas Michelle Ryan had only really been in EastEnders.)

I enjoyed it while it lasted, but it ran out of inspiration long before the end of its 2nd (and last) season.