Since the 1860s, Nicollet Avenue has been downtown's retail street. It was transformed a century later by the landscape architect Lawrence Halprin into Nicollet Mall — the charming place where Mary Tyler Moore threw her tam into the air.

But that was when Nicollet had at least four department stores and online shopping had yet to be invented. Now slated for its third completely new streetscape in less than 50 years, civic leaders promise that the Mall's renovation will make us throw our hats in joy again. It will draw more people downtown, spur economic development and investment, revive retail and entertainment, and boost property values.

The problem is that the histories of landscape architecture and planning show that design solutions and public art alone rarely revitalize urban spaces or downtowns. The new mall concept looks great in computer renderings, but it may never achieve any of its stated goals because we are confused about what Nicollet Mall really is — both historically and in the future.

We are hoping that the mall will grow into a landscape of alluring city destinations that it can never really be.

Field Operations, the project's lead design landscape architects, gained fame for their work on the High Line — lower Manhattan's elevated freight train tracks reinvented as a brilliant linear walkway. But one stunning success does not guarantee another in a very different place. Minneapolis is not New York and the High Line is not a public street. It is a privately managed linear walk and international tourist destination.

Nicollet Mall is actually something more humble yet equally important. Nicollet is historically our Main Street and not a park or walkway. It is a public space and outdoor room framed by walls of buildings, many of them — like the old Dayton's, Young-Quinlan and IDS — great ones. The High Line offers views outward to skylines of the meatpacking district, Chelsea and the Hudson, the visual drama of Nicollet is its internal views up and down the street, into window displays, and to the tops of buildings.

This space of commerce would be compromised if filled up with elements such as the proposed "Art Walk" and "Light Walk" between 6th and 8th streets. On the IDS side, the Light Walk is envisioned as a series of mirrored fins and LED lights set atop long trellises that, the design team claims, will "create a dynamic experience from below, leveraging the activity and movement on these blocks every day, while also creating a unique dialogue with the skyways above."

Or maybe, dialogues with skyways aside, the fins will just block the views of the sky itself and buildings along the street — rather like construction scaffolding, which is temporary.

On the Macy's side, the Art Walk promises a series of lanterns customized by artists under which seasonal events such as bocce and curling could happen. It might be lovely, but you will have to visit the Mall at night to appreciate these glowing orbs. Like fashionable retail interiors, all of this will eventually grow tired. And when that happens, the great volume of the street will still be there.

Not a sculpture collection

Civic leaders assume that new public art will attract people to the mall. But why? Yes, Millennium Park's stainless steel "Cloud Gate" by Anish Kapoor (affectionately called the "Bean") is a major new Chicago tourist attraction and a great spot to take a picture. Much more enclosed and compact, Nicollet Mall is not Millennium Park — a 25-acre, $475 million lakefront park intended purely for recreation in a region of 8 million people.

Recently, the city approved a plan to allot $500,000 to commission a "signature" work of art for the mall project along with an equal amount for small artworks and public features. It's still unknown how many of its 16 existing sculpture/artworks will survive this redo — many of them well-crafted.

But some think we need more sizzle. As reported by the Star Tribune, Mary Altman, the city's public art administrator, claimed that, "The collection does not have really a signature work, a work that is a draw to the mall." Hence the $500,000 blockbuster. It could be great, but will it really draw people?

Stores on the street

Rather than spending millions to rebuild a streetscape with the latest styles in landscape architecture and public art every 15 or 20 years, it makes more sense to understand what really makes a city work. Nicollet Mall and Minneapolis don't need more signature artworks and amenities like the fire pits suggested for the mall at the Loring Greenway. We need memorable businesses like bookstores, coffee shops, art galleries, clothing stores — the distinctly local, fine-grained retail mix that is the one thing proven to draw people to a downtown street.

But such local businesses need affordable rents — precisely what disappears with special assessments for elaborate streetscapes and the rising downtown property values hoped for by the city.

That's why some of the money that we are spending on the current Mall scheme might be better spent to create a trust fund to subsidize the rents of small and unique businesses along the mall and to help the underserved people who spend their days there.

The simpler and more basic parts of the Mall's proposed design, such as paving, groves of trees, and the movable chairs beneath them could work very well and last for many years. But let's not fall for the idea that art and redesigns alone can make a great street thrive.

Frank Edgerton Martin is a Minneapolis writer, landscape historian and planner based in Minneapolis.