In the old days one could easily empathize with some characters, thus many situations ended up as funny ones.
Now a days, it's like they try to convince us to empathize with them by giving some explanation, or justification, or a character's actions. It seems like all characters tend to justify their actions somehow, as a parody of themselves.
Could those changes be due to a change in the target audience? How has the show objectively changed over time?
Initially, the show was intended as a broad audience. I started watching the series as a kid, and even as an adult I find it funny, at least the earlier seasons. Now the show seems more like SpongeBob SquarePants or The Fairly OddParents.
The following are some interesting data:
List of showrunners throughout the series' run:
- Season 1–2: Matt Groening, James L. Brooks, & Sam Simon
- Season 3–4: Al Jean & Mike Reiss
- Season 5–6: David Mirkin
- Season 7–8: Bill Oakley & Josh Weinstein
- Season 9–12: Mike Scully
- Season 13–present: Al Jean
Maybe it could be related somehow.