That said, Chile happens to be producing some of the world’s most gifted architects right now, a generation that includes Cecilia Puga, Sebastian Irarrazaval, Pezo von Ellrichshausen, Mathias Klotz, Teresa Moller, Smiljan Radic (“the best architect in the country,” Aravena tells me) and Aravena. On top of the prize, Aravena is directing the current Venice Architecture Biennale, whose socially minded show he has titled “Reporting From the Front.” Naturally, this has brought skeptics out of the woodwork. Young for an architect, at 48, they note, relative to other Pritzker winners he hasn’t built a lot; and some of his signature projects, including Constitución, are still in medias res, so it’s not entirely clear how they will actually turn out. Moreover, he and his partners at Elemental — Gonzalo Arteaga, Juan Ignacio Cerda, Víctor Oddó and Diego Torres — concentrate on social housing. “The more monotonous, dry, tough, the better,” as Aravena himself puts it. “Given that people will construct homes for themselves anyhow,” he elaborates, “this architecture gives order to their interventions.”

“We don’t think of ourselves as artists,” he adds. “Architects like to build things that are unique. But if something is unique it can’t be repeated, so in terms of it serving many people in many places, the value is close to zero. We go into fields where the chance of failing is higher than average. We make mistakes. If we need to replace a window or make some other fix, it’s easier for us because we’ve built up an account of good will.”

Meaning, overall, the work is not the poetry in glass or curvaceous spectacle that has tended to woo Pritzker jurors — one of whom, as it happens, Aravena used to be, until he quit the jury only a year ago. The prize clearly acknowledges a sea change in architecture, which not everyone agrees with. “Aravena,” sniffed Rowan Moore, critic for The Guardian,“has some of the trappings of the starchitect: a high media profile, a globe-trotting, lecture-giving lifestyle, a carefully cultivated look, a bizarre hairstyle (think desert roadkill) that seems to get spikier and more top-heavy with every transcontinental flight” — as if engaging in public debate about the built environment and the role of architects makes him a media hound. It’s the usual Catch-22: Architects who don’t speak out are hermits. As it happens, Aravena promised his family he wouldn’t leave Chile more than once a month, which, with site visits to far-flung projects, means he has time for three or four lectures a year, he told me.

Before arriving in Chile, I had been told by some of Aravena’s colleagues that he’s standoffish. I found him earnest, open, a little nerdy — and deadly serious. This is an era of unprecedented urban growth, much of it informal, which is to say illegal slum development. The total number of displaced people in the world now rivals the population of France. Climate change is reshaping the globe. For architects, today’s challenges and opportunities are historic. “In the name of artistic freedom, architects made themselves irrelevant,” Aravena says. “I think we may look back and see this as a tipping point.”

If so, one place we’ll look to is Constitución. After the tsunami, construction companies there floated the predictable and self-serving idea of erecting an immense protective sea wall, which would have made a kind of fortress, or prison, of the ravaged riverfront. It’s a proposal politicians love: A wall is an impressive-looking thing they can cut a ribbon standing next to. But residents, in public meetings, had bigger concerns. Tsunamis were rare. The city flooded regularly, they complained. There was next to no green space, inadequate housing, little access to the river, poor roads and miserable public buildings.