The show has not become crappy and there has been no definitive shark jumping moment.Well, except for that time when Fonzi tried to jump the shark pit in Episode 411 (and didn't quite make the jump).
I agree that the show really hasn't jumped the shark, but there have been three phases of the show so far, and certain fans tend to gravitate toward a particular phase of the show. The first three seasons were the "Third Grade" years, where the show found its legs and hit its initial stride. The movie was released around the end of this period, and the speed of its narrative had an impact on the show.
By the fourth season, the speed of the show had greatly increased. This season, and the next, featured scripts that were up to 65 pages. For a 22 minute show, this is an insane amount of dialogue and action. In interviews, Matt and Trey said that the increased speed was intentional, but they couldn't keep that pace forever.
The current phase, marked by these last two seasons, have featured some fine episodes. But some fans miss the fast-paced action of "Trapper Keeper 2000" or "When It Hits The Fan". Some of my favorite episodes come from this last phase, but I will admit that I loved the fast pace in the beginning of the Fourth Grade years. Matt and Trey have said that they won't be returning to the hectic pace of that period, though, and I think that's why some fans might feel that the shark was indeed jumped.
The show has three main strengths that should allow it to go on for a long time IMO.
1) Less than 20 episodes are created each year. This gives them plenty of room to breath, and avoid treading over the same material.
2) The shows are produced in less than two weeks, sometimes this even includes the script. This allows them to easily spook current subjects like Paula Poundstone or Catholic priests.
3) Trey Parker. He claims that they only had one main goal in Hollywood, "Sell Out As Fast As Possible." Of course, he has yet to really sell out to any specific group. He spends an equal amount of time pissing off both Conservatives and Liberals. He takes a lot of shots at religion, but he has also equated atheism with "shit pouring out of your mouth". By being an "Equal Opportunity Hater", he keeps the focus on "humor".
I'll be watching the show until 2006 (or longer), but I can't help but feel that we'll never have an episode as perfect as the battle between Barbra Streisand and Robert Smith (The Cure) in the first season. I can laugh myself sick just thinking about Robert Smith's Mothra-inspired costume.
