Even the newest city needs a supply of old buildings. In Toronto, which seems to remake itself every few years, that supply is running out.

Though few will lament the passing of the often mundane two- and three-storey brick boxes that line so many streets in this city, they play an essential role in the complex processes of civic vitality. Because they are simple structures built decades ago, their mortgages paid off long ago, they are cheap and endlessly adaptable. They change occupants and uses regularly, which allows them to keep up with the times and remain forever relevant.

This point was not lost on Jane Jacobs, pioneering urbanist and author of the seminal study, The Death and Life of Great American Cities: “Cities need old buildings so badly,” she wrote in her 1961 book, “it is probably impossible for vigorous streets and districts to grow up without them.”

As Jacobs goes on say, by old buildings, she doesn’t mean heritage landmarks, but “plain, ordinary, low-value old buildings, including some rundown old buildings.”

This is a description of what many would consider urban blight. In fast-growing Toronto, where real estate prices and development are through the roof, it’s easy to forget that these unattractive, aging heaps can be more conducive to good urban health than all the glass-and-steel condo towers in the world. Although the tower-on-the-podium model seen here is better than some in an urban context, the economics of highrise construction, condo boards and 21st-century marketing mean that most of this new street-level retail is gobbled up by the usual corporate suspects.

And the growing pretentiousness and fixation on luxury pretty well rule out mom-and-pop renters and specialty shops in favour of international operations that seek to remake the city in their own image. Their arrival brings with it the sterility of the generic, but because their pockets are deeper, bankers and owners are happy to welcome them.

As we’re quickly discovering, however, the real failure of many condos is at street level. These spaces, often poorly designed for small businesses, have only the most tenuous relationship to the city. In their desire for exclusivity, they adopt an architectural language of aloofness. They set themselves apart.

By contrast, those humble boxes that all but define Toronto are inseparable from the streets on which they are located; they are connected to them, focused on them and exist to serve them. They function as an extension of the public realm, not an exception to it. If they offer novelty, it’s because of the contents, not the architecture. Indeed, these modest buildings become almost invisible; they are the backdrop to the diversity that Toronto’s motto proclaims is “our strength.”

Yet as Jacobs also points out, “Time makes the high building costs of one generation the bargains of a following generation ... . Time makes certain structures obsolete for some enterprises, and they become available to others.”

One can’t help but wonder what fate awaits these awkward podium spaces in the future. Will they turn out to be the bargains of the future? As capital costs are paid off, will they become available to other enterprises?

Certainly, 19th-century factories, warehouses, garages and even jails have been happily given over to new uses and fully reintegrated into the economic and social life of the contemporary city. These functioned as incubators before governments knew what the term meant. They are where startups started, entrepreneurial and cultural.

Until recently, the typical response was simply to tear down the old to make way for the new. Today we know better; if the future is friendly, more likely it’s because of the past.

Christopher Hume can be reached at chume@thestar.ca