It’s a cute idea: “The Merry Wives of Windsor” as a bygone TV sitcom, replete with bell bottoms, leisure suits and perky theme songs. Shakespeare’s airiest souffle does put one in mind of all those half-hours of zaniness that once dominated prime time: clueless hicks living in Beverly Hills and horses that talk and mischievous uncles from Mars. Why not the antics of sly Elizabethan housewives playing tricks on a fatuous drunken roue?

For 15 minutes or so, as the actors at Folger Theatre assume the postures of wacky stage versions of 1970s comedy characters, the conceit has some amusing momentum.

Then the law of diminishing returns kicks in.

Director Aaron Posner’s organizing notion proves far better suited to a short skit than a full 150 minutes of expository twists — and antiquated japes. At the point of the 88th joke about the luxurious girth of Brian Mani’s Falstaff, the references not only stop being funny, they also remind you that even by the standards of ’70s sitcoms, making fun of someone’s weight is, in the contemporary vernacular, just fat-shaming.

Comedy is indeed a temporally fragile commodity, and even on the most stylish and savvy of evenings, “The Merry Wives of Windsor” is rickety and tiresome. The wives of Windsor — Mistress Ford (Ami Brabson) and Mistress Page (Regina Aquino) — here wear mod pantsuits and hairstyles and plot revenge on greasy Falstaff, as their husbands (Ryan Sellers, subbing for the ailing Eric Hissom, and Tyee Tilghman) fret and stew.

A nearly superhuman degree of skill is required to make Shakespeare’s language work under Posner’s guidelines. While audiences have been conditioned to all types of tinkering with time and geography in classical theater, situation comedy imposes on practitioners a particular level of discipline, with plotting, timing and dialogue. And though the cast includes some accomplished Shakespeareans — Kate Eastwood Norris, Todd Scofield and Cody Nickell among them — the parodistic roles into which they’re shoehorned prove to be one-note caricatures embellished with hackneyed accents. They’re using about a tenth of their abilities.

Designer Tony Cisek creates a geometric backdrop of a suburban house facade, a look that brings to mind a swath of family TV comedies, from “Bewitched” to “The Wonder Years.” (Perhaps you could subtitle this production “The Bardy Bunch.”) Costume designer Devon Painter has fun with tie-dyed shirts and astral medallions, and spectators of a certain age will recognize the period music — from “Raindrops Keep Fallin’ on My Head” to an accompaniment for a brief demonstration of the Hustle — predictably inserted for cheap snickers.

Posner goes for the laziest jokes all evening, the sort that trigger mere reflex giggles in an audience relieved of the chore of fully grasping Shakespeare’s idioms. At least the director spares us a laugh track.

The Merry Wives of Windsor, by William Shakespeare. Directed by Aaron Posner. Set, Tony Cisek; music and sound, Matthew Nielson; costumes, Devon Painter; lighting, Max Doolittle. About 2½ hours. $27-$85. Through March 1 at Folger Theatre, 201 E. Capitol St. SE. 202-544-7077.