“Company,” which runs through Sept. 10, is in some ways the least ambitious of the three, and also the most successful. By least ambitious, I don’t mean the material itself, with its Stephen Sondheim score and George Furth book; the original production in 1970 was a musical theater game-changer that remains, with its impenetrable main character and abstract action, a difficult piece to pull off.

I mean that despite a skilled New York cast led by the glossy Aaron Tveit, Barrington’s “Company,” directed by Julianne Boyd, is neither a Broadway tryout nor an attempt to reinvent the wheel. From the ’70s satire inherent in its pungent costumes to the gorgeous singing of the entire cast, it has evidently been packaged as pure entertainment.

How well that approach represents the ambivalence at the show’s core is another matter. Bobby (Mr. Tveit) is a 35-year-old singleton at the height of the sexual revolution; he insists he is enjoying his freedom but his “good and crazy” friends — five married couples — think he is just afraid of commitment. The action consists mostly of Bobby’s watching those couples bicker, and drawing what conclusions he can from the way they make up.

Time has not made the plot less problematic. A 35-year-old in 1970 apparently was more middle-aged than he is today; as played by Mr. Tveit, who is 33, there is no sense that Bobby is late to the marriage gate. And later revisions made by Mr. Furth to foreclose on the possibility that Bobby is gay now seem counterproductive. His denial comes across as more of a devious dodge than his silence ever did.

Could it be that, absent disruptive directorial interventions like those made by John Doyle in the 2006 Broadway revival, the book is becoming untenable? Instead of psychology, it gives most of the wives gimmicks: One’s a first-time marijuana smoker, another a karate enthusiast. The interchangeable husbands barely get that much. And even Mr. Tveit, though ideally cast, can’t find much to do besides taking his safari-style suit jacket on and off. His Bobby is not merely passive but disaffected to the point of depression. It’s a reasonable reaction to a plot that incessantly nudges him from point A to point A.