The transcript doesn't detail the specific content of the pivotal third episode, only that it "started to get pretty good," showcasing improved "voice, timing, and ... how to use the camera." It was this improved quality, along with Rob McElhenney's proactive approach to securing meetings, that led to the show being picked up.
This Team Coco video features Charlie Day discussing the origins of It's Always Sunny in Philadelphia. The conversation explores Day's comedic background, his initial struggles as an actor, and the creative process behind the show's conception and success, including the pivotal role of Danny DeVito's involvement.
The transcript states that Rob McElhenney and Glenn Howerton, along with Charlie Day, were all working and struggling to find acting work in their 20s. They collaboratively decided to create It's Always Sunny in Philadelphia together, shooting a pilot, then a second and third episode, before shopping the show around to producers and eventually getting it picked up by FX. Rob McElhenney's impatience was also a catalyst for them actively seeking meetings and pitching the show.