I thought of this today, in one episode Popouli and his wife celebrates their 50th aniversary and a few years later when he visits and ends up dying, she's not there and not mentioned. Should we assume at some point between episoes she passed away and they never mentioned it. Also, how come we never got to see Ggrandpa Tanner, Kmmy's parents or brother?

Sometimes unseen relatives work the best. You don't have to find actors that look similar to the main character (Kimmy's family would have to look somewhat like her, etc), you don't have to pay another actor, and the set would be less crowded. Also, let's take the Papouli episode for example. If his wife was there, the writers would have to create a storyline for her as well and the episode could become "too busy" for it's 30-minute timeslot.

Just my opinion...don't know if it's accurate or not compared to showbiz.