You’ve probably seen them — the roughly 1,400 Spirit Halloween stores that spring to life at this time every year.

The pop-up stores highly successful. They’re also, according to experts, possibly the future of retail amid a glut of commercial vacancies.

“The giant-footprint mall with the anchor stores full of inventory, counting on people going there to shop, counting on foot traffic, is not going to work very much going forward,” says Jay Prag, an economics professor at the Drucker School of Management.

He and other retail mavens say that while traditional brick-and-mortar stores will continue to dominate sales, a growing number of merchants will embrace pop-ups as a cost-effective way of reaching consumers on a limited basis.

“The idea is that you’re not paying rent for 12 months. You don’t have all of those fixed costs,” observes Darrin Duber-Smith, a marketing professor at Metropolitan State University of Denver.

“And you’re able to sort of exploit the opportunity of only working for three or four months, rather than having a store where you have to change everything out seasonally.”

Here’s the thing: The pandemic has left a glut of commercial space, with a vacancy rate of nearly 15%.

Bed Bath and Beyond, for example, says it’s closing about 150 stores as it struggles to live in Amazon’s world. That’s not going to change any time soon.

Most pop-ups are either seasonal, like what Spirit does, or buzzy, one-time-only affairs such as the ones Kanye West has rolled out worldwide. Pop-ups are estimated to pull in about $10 billion in annual revenue.

In fact, Southern California has been at the forefront of the pop-up movement for years. But not for the retail industry. Restaurants.

“The food truck is really the ultimate pop-up store,” says Duber-Smith. “And you’ve got something that can be driven around.

Until the commercial vacancy rate goes down, it’s a buyer’s market when it comes to retail pop-ups.

“The more the merrier for the commercial real estate owner, because at some point someone’s going to say ‘I want to be here permanently,'” says Miro Copic, a marketing professor at San Diego State University.

“And that means that they have a long-term rental agreement as opposed to working hard to fill space every few months.”