Of course, “Simpsons” episodes have not been locked away in a closet, like prized baseball cards. For two decades, repeats of “The Simpsons” have been widely seen on local broadcast television stations. Every other sitcom hit of recent vintage, from “Seinfeld” to “The Big Bang Theory,” has been made available in multiple sales to broadcasters and cable networks alike. Studios rarely leave such opportunities on the table.

But “The Simpsons” was locked into an unusual — and now vintage — deal. The show was first sold into syndication in 1993. While an enormous hit for Fox, “The Simpsons” always stood out because it was animated. When Fox tried to place live-action comedies adjacent to it, they never really worked.

So the stations paying hefty rights fees insisted on maintaining exclusivity — meaning no sale to a cable network for as long as they were buying new seasons of reruns. “The Simpsons” — with a cast that never visibly aged — kept making new episodes on Fox, and the syndication contracts kept going.

Until now. The studio has finally worked a way to open the cable window, one that has long been estimated to be worth a fortune to a show that already is one of the greatest moneymakers in entertainment history, considering the value that has been reaped from merchandising, a theme park attraction and a theatrical movie.

For the fledgling FXX network, the deal is clearly intended to be a foundation stone. FX, known mainly for well-regarded dramas like “The Shield,” “Nip/Tuck,” “Justified” and “Sons of Anarchy,” spun off its comedy lineup (“Louie,” “It’s Always Sunny in Philadelphia”) in the all-comedy network starting last September.

The results so far have been lackluster. Ratings for shows that have moved from FX to FXX have been nothing close to what they were in the past. In the most prominent example, the late-night talk show, “Totally Biased With W. Kamau Bell,” had more than 300,000 viewers on FX but fell to fewer than 50,000 on FXX and was canceled this week.

Now FX will have a core of comedy programming with the longest track record in television history.

Paying the hefty price has less sting because the money essentially moves from one corporate pocket to another — minus the many millions that will be paid to the profit participants in the show, which include, among many others, Matt Groening, who created the original comic characters, and James Brooks, the famed television and movie creator, who brought the show to Fox 25 years ago.