A rare groove indeed

In this post, Curbed.com mentions that architect Barbara Bestor of Bestor Architecture recently spoke to KCRW DJ Garth Trinidad on the air about her work, one example of which is below:

Does anyone else spy an unhappy hipster in the window?

Quoth La Bestor in the interview: "I try to get the rare groove that’s going to last, so that thing will work for like 20 years no matter what people will do to it."

"Like 20 years"??

Is two measly decades the longest we can expect our buildings to last and be serviceable in their originally designed form? Shouldn't architects—and their clients—set their expectations several magnitudes higher than this?

A few older Los Angeles architects seem to have understood the value of designing buildings that would last indefinitely:

Chateau Elysee, 1928: 82 years old and going strong

Mission San Fernando, 1797: 213 years old and still functioning as a church

Why do we settle for throw-away buildings? Why do architecture schools teach that buildings should have a shelf life, like mayonnaise? Just wondering . . .