Historic preservation of buildings is a good thing. Motivated mainly by desire to see railroad stations and structures preserved, I joined the National Trust for Historic Preservation around 1980.
But preservation isn't limited to buildings from the 19th century or before. Longevity of 20th century buildings in the Art Deco, International, and Modern styles fell into jeopardy, with debates over the appropriateness of preserving examples of these styles. Some have been razed despite outcry.
The same arguments now erupt over Brutalist buildings. Brutalism emerged in the 1950s and was widespread for 30 years. If you've seen a blockish concrete exterior, it's probably Brutalist. From the outset many people despised them as ugly. As the buildings have aged, their concrete facades have proved to be vulnerable to spray-paint graffiti and stains from rust and moss. Furthermore the concrete interiors are not always easy to retrofit for office wiring.
For all these reasons Brutalist buildings are at increased danger of destruction. I believe this is regrettable. In every style of architecture there will inevitably be buildings that were ill-conceived or poorly constructed; I don't argue that every Brutalist building should be preserved. There is a horrid Embassy Suites Hotel not far from my house that I'd like to nominate for imminent destruction.
I find many Brutalist buildings attractive, however. Along with shopping malls and repurposed gasoline stations, they are the architectural legacy of the Baby Boomer generation. Let's not destroy them all. In another 25-50 years, Brutalism will be better appreciated.