Why do cartoons and other American shows never change openings?

[Kirameo]

RolStoppable said:

Soriku said:

RolStoppable said:

So any changes in the opening count?

The openings have to be completely changed. So some new scenes in openings you've already seen don't count.

Okay, here are some I can think of:

Kim Possible - The season 4 opening still has the same song, but the scenes shown were all from season 2-4 (only season 1 before).
Two and a half men - Only had a jingle and the title at first, later on got a longer opening.
Will & Grace - At first only the title and short music, later on a full opening with a much longer version of the theme.
Married... with kids (I think that's how the Al Bundy show is called over there) - Updated the opening three or four times, although it always had the same acting and song.
That '70s show - Same music, but new opening.

That's five examples. Start watching some good shows for once, then you wouldn't have to made such a silly thread.

I'd like to add that most of the time (if not always), the songs don't change because they become like a part of the show. I'm sure if I ever listen to a song of that kind of show I would inmediately relate it to the show.

However, in anime it's not quite like that because as the plot evolves, it's necessary to change the opening to keep up with the current feeling of the show (introducing new characters, or simply different arcs).

In western shows there is actually little to no evolution in the plot (there are exceptions of course!) but those that you mentioned are just casual shows that revolve around a simple theme. 

I'm no expert on the subject so don't take my word for it.