From what I remember Optimus came back twice in the G1 cartoon.
Yes but, even as a child untill I saw the movie I didn't think the Autobots could die. And there was never really much threat of the main characters suddenly and shockingly being lost in the G1 toon, and if they were you knew they'd be back. The movie trying to create a more serious all ages atmosphere, nedds to have Decepticons who are a credible threat. If Jazz hadn't fallen then Megatron and the rest of the Deceps would look like a bunch of losers.

Prime also waited a good half a season+ before he came back to.