Because of Adult Swim ratings and DVD sales.Futurama,
Because of DVD sales.Family Guy, revived from cancellation.
Aside from the names of the characters and the design of Galactica, it was a different show...and as mentioned above when it wasn't worth it to produce it was canceled.BSG revived by reboot.
But Futurama and Family Guy weren't revived out of charity to Groening or McFarlane. They were making money. The n
TNG - the most popular series of the Berman/Moore/Branga era bombed in terms of remastered DVD sales. The demand isn't there which means the money isn't there which means the networks won't be there.