Although That 70s Show set up two different replacements for Eric Forman in its final season, the hit sitcom couldn’t get either of these characters to stick. It is never easy when a beloved character leaves a successful sitcom. All TV shows rely on the chemistry between their cast members to succeed, but sitcoms are particularly vulnerable to cast shake-ups. Since sitcoms are character-driven rather than plot-focused, they tend to rely heavily on specific cast members. This was certainly true for That 70s Shows cast, who fine-tuned an iconic dynamic throughout the show’s first seven seasons.

https://screenrant.com/that-70s-show-season-8-eric-forman-replacements-randy-charlie-fail/