Meryl Streep has a new HBO Max movie called “Let Them All Talk,” in which she co-stars with Candice Bergen and Dianne Wiest, with Steven Soderbergh both directing and operating the camera.

During a recent appearance on Stephen Colbert’s show, Streep raved about the fact that there was no script, just an outline which the actors had to improvise scenes from, claiming, “I don’t think anyone’s ever done that in a movie before!” Well, let’s see, just off the top of my head there are the Christopher Guest movies (e.g. “Waiting For Guffman,” “Best In Show”), Rob Reiner’s “This Is Spinal Tap,” Charlie McDowell’s “The One I Love” (with Mark Duplass and Elisabeth Moss), and Lynn Shelton’s “Your Sister’s Sister” (also with Mark Duplass, plus Emily Blunt and Rosemarie DeWitt).

But here are some blunt truths about so-called improvised movies (or TV shows like Larry David’s “Curb Your Enthusiasm”). What we end up seeing is rarely the first thing that the actors came up with. From the outline, they shoot multiple takes, then cobble together the best lines into the final product, which is also heavily edited — so it includes different bits from different takes. No, it’s not fully scripted, but it wasn’t entirely made up on the spot in one long take.

If everyone were being honest, they’d tell you that a well-written movie or TV show is almost always better than an improvised one, because there’s an editing process, which winnows out weaker material. Even when all the words are on the page, it still gets toyed with by the director, the writer, and the actors, all of whom hopefully make those words better (assuming they’re in a position to be allowed to ad lib and not in a David Mamet or Aaron Sorkin project, where the verbiage and cadence matter).

If you go see Second City (in Chicago, Toronto, or one of its road companies), you’ll see sketches that may have been birthed in an improv session, but were then honed through repetition and addition into something deemed worthy of sharing with the audience nightly.

In the mid-1980s, Martha and I used to go into New York City to see a troupe called Chicago City Limits, which did something different. They presented an evening made up entirely of improv games with audience suggestions, but rendered by extremely talented comic actors who were brilliant thinking on their feet.

I even went to take classes there to learn some of the ideologies behind the structures that had been built decades before by masters of the genre like Viola Spolin and Del Close. While I learned some things about working in an ensemble that helped my later radio work, I’m here to tell you that although there were some hilarious things said and done, none of it was as good as if it had been preplanned and prearranged.

One of the things those CCL cast members hated was when audience members made suggestions that were designed to get a cheap laugh (e.g. anything scatological or sexual). But because they were committed to accepting the first thing someone shouted out, they were often stuck in scenarios like a visit to a proctologist or a hooker picking up a businessman. Yes, they got laughs, but they weren’t proud of them.

You can still see this dynamic being played out today at CCL, Upright Citizens Brigade, or any other improvised-sketch troupe. It’s also on display on episodes of “Whose Line Is It Anyway?” with Ryan Stiles, Colin Mochrie, and Wayne Brady. As quick-witted and talented as they and their guest stars are, too many of their bits fall into that same cheap-laugh hole. Moreover, the segments that fell flat have been edited out of the final telecast.

I mention all of this because of Streep’s claim about “Let Them All Talk.” No, the movie doesn’t go for easy laughs. There’s nothing funny at all, for that matter. It’s a very dry, slow slog.

Streep plays Alice, a famous writer who’s been chosen to receive a literary award in England, but since she can’t fly, her publicist suggests she go by boat, specifically the Queen Mary 2. Alice invites her two oldest friends. Candice Bergen is Roberta, who’s bitter that Alice ruined her life by using some of their shared history in one of her first novels. Dianne Wiest is Susan, who is, well, just like every other character Wiest has ever played. For some reason, Alice’s nephew (Lucas Hedges) goes along, as does the publicist (Gemma Chan).

As they cross the Atlantic, the characters engage in short scenes (maybe the actors could only improvise a half-dozen lines at a time) that reveal very little other than Alice’s diva qualities and Roberta’s desire to meet a rich man. Nearly all of this exposition is boring as hell, as is a side story about a very successful crime novelist who happens to be on the boat, too.

Soderbergh and his cast shot the movie during an actual crossing of the Atlantic, with paying customers on board as unpaid extras. He’s such a good cinematographer that he makes the luxury liner and its ocean views look so appealing I’ll bet some viewers will try to book passage on this or some other cruise ship, forgetting about the large number of such vessels whose passengers and crew were stricken with a virus (COVID, Norwalk, or otherwise).

After sitting through “Let Them All Talk,” I sincerely wished for the opposite, that someone would tell these characters to just shut up. That improvisation would have made me laugh out loud. But since it didn’t happen, and I can’t get back the nearly two hours I wasted watching the movie, the best I can do is warn you to stay away by giving “Let Them All Talk” a 3 out of 10.

The moral of the story is: Writers Matter.