With nary a whimper, an era has come to an end. At 11:59 pm on Mar. 12, 2010, the elegantly utilitarian redbrick building at 548 West 22nd Street, the former home of the Dia Foundation for the Arts, locked its doors. Most likely, it will never be an art space again. In a city with so little first-rate institutional exhibition space, and so much bad space, this building’s near-perfect 36,000 square feet will be dearly missed. Especially because there will always be the terrible feeling that it didn’t have to be this way -- that institutional hubris, shortsightedness and mismanagement created this sad situation. The closing is the grim symbol of a deeply misguided expansion era for many museums, one that is only now ending.