Jane Fonda and Lily Tomlin star in Netflix’s cliche-filled new comedy, “Grace and Frankie.” (Melissa Moseley/Netflix)

Netflix’s disappointingly rote “Grace and Frankie” stars Jane Fonda and Lily Tomlin as women whose law-partner husbands, Robert and Sol (Martin Sheen and Sam Waterston), have come out as gay lovers and have plans to marry.

Robert and Sol each initiate divorce proceedings from Grace and Frankie, leaving the two septuagenarians, who were never great friends to begin with (Fonda’s Grace is a rigid former CEO of a cosmetics line bearing her image; Tomlin’s Frankie is a hippie-dippy painter who teaches art to ex-cons), to reluctantly rely on each other for support. Because this is a television comedy, “support” is defined here mainly by the cutting remarks and barbed insults that form most of Grace and Frankie’s conversations and yet somehow (inexplicably) translate into shared sympathies.

“Grace and Frankie” is mainly a reminder that for all the revolutionary talk, Netflix is as susceptible as anyone else to serving up conventional, lukewarm fare. Things start off slowly and pick up slightly from episode to episode; six episodes in (out of the 13 that begin streaming Friday), the show is far from anyone’s idea of a flop. There are too many talented people in it — especially Tomlin — and enough stray LOLs to prevent a disaster.

But the show dawdles in a long and empty corridor that separates edgier, topical character studies such as Amazon’s brilliant “Transparent” from a traditional comedy series such as “Friends” (for one example), the perpetually syndicated hit helmed by “Grace and Frankie” co-creator Marta Kauffman. With some sharper thinking, “Grace and Frankie” might be a worthy rejoinder to “Transparent,” particularly in how Robert and Sol come out and how both Grace and Frankie insist they never saw this news coming from the men whom they had married and raised children with for 40 years.

Latent declarations of homosexuality are frequent enough that “Grace and Frankie” should have been able to imagine a story that was deeper and more realistic — and, of course, more wry. In the first few episodes, both Sheen and Waterston seem desperate to find material in the script that might help them convey Robert and Sol’s love (and anguish) past the point of a rudimentary outline, but that material isn’t provided, certainly not in the way it was provided to Jeffrey Tambor, who in “Transparent” plays a father in his late 60s who reveals to his adult children and ex-wife that he’s becoming a woman.

Where “Transparent” was a comedy (of sorts) preoccupied with verisimilitude and heartache, “Grace and Frankie” is distractingly afflicted with the laziness of cineplex-style romantic comedies, minus most of the romance. Devastated by their husbands’ deceit, Grace and Frankie seek refuge in a beach house that the couples purchased jointly, years ago, in friendlier times.

Jane Fonda and Lily Tomlin star as two women whose husbands leave them for each other in “Grace and Frankie.” (Melissa Moseley/Netflix)

Sam Waterston and Martin Sheen play the husbands in “Grace and Frankie.” (Melissa Moseley/Netflix)

The beach house is, of course, fantastic and huge, a prime example of the property porn that became a risible feature of Nancy Meyers’s older-gal rom-com genre in the 2000s (“It’s Complicated,” “Something’s Gotta Give”), where the designer kitchens, furniture and linens make it nearly impossible to tune in to the so-called problems a character might be having. (So your husband is gay! You just wrapped a $400 throw around your shoulders!)

Which is not to say that this story couldn’t or shouldn’t be about wealthy people. Rather, it’s that “Grace and Frankie” has a far too casual approach to the details on a mistaken assumption that its story (and stars) will carry the day.

Tomlin is therefore forced to draw from the same kind of pot-smoking New Age woo-woo she’s played more than once, while Fonda is again cast as a Teflon toughie bent on preserving her two-olive-martini WASP exterior. I’m fairly sure we covered most of this material way back when “Dharma & Greg’s” mothers first met. And not to get all “Freaky Friday” on this, but I wonder if Kauffman and co-creator Howard J. Morris at all considered the possibility of Tomlin and Fonda switching roles. If not, why not?

“Grace and Frankie’s” limited sense of imagination is as plain as the chair upholstered with an image of Ryan Gosling’s face that Robert and Sol special-order for their new household (because they’re gay, get it?) or the peyote tea that Frankie guzzles on the beach in an attempt at some mind-blowing catharsis (because she’s a hippie, get it?).

Some of these tropes are leavened by naughty writing (“I must have half the beach in my vagina,” Frankie deadpans as she staggers back to the house after her drug trip), but there are long spells of ho-hum involved, especially when the story keeps shifting to Frankie and Grace’s adult children, whose own minor quirks and problems (ranging from addiction recovery to stay-at-home-mommy ennui) fail to spark much interest.

In fleeting moments, it might seem that “Grace and Frankie” intends to provide a new take on aging and mortality — and since Netflix allowed critics to screen only the first six episodes, there’s always the chance that the back half of Season 1 will find a deeper and more meaningful story to tell about getting old.

There’s a marvelous image in the first episode of Fonda disassembling her character’s illusory mask of flawlessness by removing makeup and hairpieces and unfastening a magic clip at the back of her head that keeps her face taut. Similarly, when Tomlin’s Frankie applies for a job teaching art at a nursing home and is instead taken on a tour for prospective residents, she is gravely insulted: “My joints are supple!” Frankie yells, performing a deep, impressive squat.

Speaking of agility matters (and requiring a short beep-beep from my spoiler alert), there’s a scene in Episode 4 where Grace slips in a fro-yo shop and breaks her hip, which requires replacement. Her doctor (Corbin Bernsen) also detects signs of a head injury or possibly a small stroke. For so many people who are Fonda’s (or Grace’s) age, a fall like that can mean the beginning of the end.

But in “Grace and Frankie,” it’s merely a hallucination and a metaphor: Frankie catches Grace when she slips. Which means she never really fell; she merely glimpsed a flash of the horrors of being the sort of human who grows old.

All right, fine. Both Fonda and Tomlin have defied age enough that they might look silly piloting their Buzzarounds through a casino or languishing in hospital beds while prone to infections.

Yet the fact remains that Fonda is 77 in real life — slightly older than her father was when he made “On Golden Pond” and three years older than Katharine Hepburn was in that film. But instead of playing “old,” she’s playing a character who is 70 and who passes herself off as 64 in an online dating profile. Tomlin, meanwhile, is 75; Waterston and Sheen are 74. In other circumstances, they could all be playing the cranky, zonked-out patients in HBO’s “Getting On.”

Age is just a number, it’s true, but it’s a number that averages out to zero when “Grace and Frankie” relies on the same old silver-fox delusions featured in AARP ads. When all is said and done, we don’t need more shtick about marital betrayal and who gets to keep the beach house, but we could still use more good, provocative dramedies about the Medicare years.

Grace and Frankie

(13 episodes) begins streaming Friday on Netflix.