It is unlikely that Family Guy will continue forever.
While the show has been a consistent success for Fox, and its creators have expressed interest in continuing, the show's future is ultimately determined by factors like viewership, production costs, and the availability of its creative team.
The show has been renewed for its twentieth season, but even long-running series like The Simpsons have faced declining viewership and eventually ended their runs.
The show's creators have acknowledged that Family Guy could end at some point, and they've expressed a desire to leave on a high note rather than overstaying their welcome.
Even if the show's creators remain enthusiastic, the show's future is ultimately dependent on the network's decision, which is based on factors beyond creative control.
While there's no guarantee of a forever run, Family Guy has consistently delivered laughs and remained a cultural touchstone for over two decades, demonstrating its enduring appeal.