Dreamworks' "Shrek Forever After" opened with the third-highest opening weekend of the year—behind only "Iron Man 2" and "Alice in Wonderland"—with over $70 million domestic (estimated). 

A triumph? Not really.

Here are the opening weekends for the four "Shrek" movies. All numbers are adjusted to 2010 dollars:

* Top Critics Only
** All numbers are adjusted to 2010 dollars

That's quite a comedown.

Obviously new films tend to open weaker than sequels, which is what happened with the first "Shrek." But because "Shrek" was good (86% rating on Rotten Tomatoes) it went on to gross $375 million, or no. 3 for the year.

And because "Shrek" was good, its sequel, "Shrek 2," opened gangbusters: $138 million. And because "Shrek 2" was good (88% rating on RT) it went on to gross $564 million, or no. 1 for the year. In fact, until "Dark Knight" and "Avatar" came along, it was the no. 1 movie of the decade.

And because "Shrek 2" was good, its sequel, "Shrek the Third" opened gangbusters: $140 million. But because "Shrek the Third" wasn't good (49% on RT) it went on to gross only $372 million. I know: "only." But that's a $200 million drop from the previous film.

And because "Shrek the Third" wasn't good, its sequel "Shrek Forever After," opened with half the numbers of "Shrek the Third": $71 million. And because "Shrek Forever After" isn't good, either (40%), I assume it'll gross even less. Will it gross $250 million? Will it outdo "How to Train Your Dragon," which is already at $210 million?

Other factors could be at work, of course. The world's complex. Maybe there were simply better options this weekend. Maybe people are finally tired of this 10-year-old franchise. Maybe we don't have the patience for any fourth movie.

But in general I think the above is how moviegoing works—and it tends to be ignored by the powers-that-be. If you keep making a quality version of a beloved product, people will show up. Once the quality slips, the audience slips.

BTW: When referring to "good" and "bad" versions of "Shrek," I'm talking about the general critical reception, which, I argue, and have argued, is on par with general audience reception and word-of-mouth. Me, I only saw the first "Shrek," which I didn't like.

Look, Donkey! Maybe people are finally sick of us!