If we're being entirely honest it was a different show entirely, on a different network, that just happened to have a few of the same actors playing mostly the same character. They certainly tried but there wasn't enough there to make anything and they specifically only wanted a single extra season as an experiment to see if the audience would migrate networks. They didn't.
Dude! The jump from season 8 to season 9 was so bad, they couldn't even connect the line!
If we're being entirely honest it was a different show entirely, on a different network, that just happened to have a few of the same actors playing mostly the same character. They certainly tried but there wasn't enough there to make anything and they specifically only wanted a single extra season as an experiment to see if the audience would migrate networks. They didn't.