Tower Records was the last survivior of the time twenty or thirty years ago, when most records (LPs in those days) were sold through distributors called "rack jobbers" who sold nothing but the top selling titles.
Tower and the long-departed Discount Records chains were created or encouraged by the major record labels as places that would have extensive inventories of backlist -- if you wanted something like a five-year-old title by the Modern Jazz Quartet, or a Vivaldi concerto played on original instruments on the Archiv label, or something out of the Folkways catalog, or even a non-current record by Perry Como or Hank Snow, those stores were the place to go. And they allowed the labels to keep that stuff in print and maybe make a small profit on them.

But today, you go to the online retailers like CCMusic and Amazon for backlist, or you download music files. There's no need for expensive inventory in hundreds of separate stores.

It's sad, but the big stores have outlived their useful places in the retail food chain. But on the positive side, with Tower gone, the smaller specialty stores will have less competition.