Who’s to blame for spate of closings?

What is Las Vegas going to do with all these problem children?

Six or more theaters in the resort corridor have been a revolving door for failed shows, to the point where you can ask how much of the problem lies with the room itself — or at least those in charge. (To paraphrase the gun lobby, the chairs don’t make themselves empty.)

We speak of this now because the Tropicana, once again, has a brandnew show facing a tough challenge. “Band of Magicians” had its official debut Thursday, only a week after the closing of “Cherry Boom Boom.” Now the Australian-born magic collective, presented here by Steve Sterling’s Senterstage Productions, is going it alone in a place where other producers claim a roommate is essential.

The historic showroom is still under contract with Local 720 of IATSE, the International Alliance of Theatrical Stage Employees. Producers say they can’t handle the union costs on their own, given the reality of average attendance far below the room’s “Folies Bergere” heyday (when the hotel also bankrolled the show).

At one point, “Cherry” co-producer Lynn Garlock-Wright says, three productions were to share costs. The curveball came when “Raiding the Rock Vault” abruptly gave up and closed, leaving “Cherry” stuck in the middle until

The bigger mystery is why the old Tropicana showroom can’t get more traction, given its prime location and a gorgeous makeover. Even the Broadway blockbuster ’Mamma Mia!’ flopped there.

the “Magicians” showed up. “We carried the entire IATSE bill for three months, which was way too long for any producer to sustain,” she says.

(Waiting for “Band of Magicians” to open would have meant losing dancers to other gigs after 12 weeks of rehearsal, she added. It still might have been prudent, but hindsight’s 20-20.)

The bigger mystery is why the old Tropicana showroom can’t get more traction, given its prime location and a gorgeous makeover. Even the Broadway blockbuster “Mamma Mia!’ flopped there.

But this problem child has siblings:

WESTGATE LAS VEGAS

Once the proud Las Vegas Hilton, where Elvis sweated up scarves, the showroom is now leased out to a production company, Red Mercury Entertainment, which is leaving it dormant after the misfire “Twisted Vegas.” A long hike from the Strip, the Westgate theater always worked better for concerts or resident headliners. But to get back in the concert game now would mean competing with The Pearl at the Palms, the House of Blues at Mandalay Bay and The Foundry at SLS Las Vegas.

THE ROCK OF AGES THEATER

The Rio’s circular venue will have to change its name when the Broadway musical folds at year’s end. The room most proudly associated with Prince 10 years ago now has a two-named problem: Penn & Teller. The magicians — and those dancin’ dudes in Chippendales — make you question whether an off-Strip casino needs a third venue.

PH SHOWROOM AT PLANET HOLLYWOOD

This deal seemed too sweet to fail. Planet Hollywood’s original chairman, Robert Earl, gave producer Base Entertainment a 30-year, rent-free lease in return for the build-out of the theater and the rights to run it. But the room has been a historic underperformer since it opened with “Stomp Out Loud!” in 2007, brightened only occasionally: “Peepshow,” when Holly Madison had “Holly’s World” on E! and Jeff Dunham, when AEG Live leased the room for a residency. The larger Axis Theater, running at full throttle with Britney Spears and other stars, seems to suck a lot of oxygen from the upstairs venue.

THE PALAZZO THEATRE OR OPALINE THEATRE

Why can’t I just pick one? Hey, that’s management’s job. The Rio’s crowding issue also applies to the four show venues at the connected Venetian and Palazzo. The casinos eased in-house competition by not rushing to replace “Rock of Ages” in the Opaline (which did host Al Pacino for one night last month), giving the uphill battles of “Baz” and Clint Holmes a needed boost in the artfully remodeled Palazzo theater.

THE PLAZA

Have the Scintas finally brought some salvation to downtown’s retro showroom? It’s one of the few places to see what Vegas used to look like, but its history is otherwise so sad it’s hard to even talk about it.

HONORABLE MENTION: THE “JUBILEE” THEATER AT BALLY’S

The stagehands union may again be a reason why this theater is apparently off the market for a year. The 70 stagehands outnumbered the dancers when “Jubilee” closed in February, all of them hotel employees. Backstage modernization and a long enough dormancy to void the decades-old “Jubilee” contract should put this one back in action.

So there you go. Social workers will tell you the real trouble with most problem children is the economic environment around them, and/or the lack of strong parenting. Just don’t blame the empty chairs.

COURTESY The Australian-born magic collective “Band of Magicians,” which had its official debut Thursday, is going it alone in the old Tropicana showroom, a place where other producers claim it’s essential to have a roommate to share the cost.