In Boulder, Cambridge, Milwaukee and Seattle these stores are considered "niche retail." While brick and mortar bookstores have been hit hard by online sellers like Amazon, these shops supply a definite niche in poetry.
An article in The New Yorker describes what it calls The Curious Persistence of Poetry Shops, they say that "The countercultural appeal of poetry, like that of art, makes it a relatively easy sell to a population willing to shop for things that they don’t necessarily need but might covet as a form of self-expression. That niche is centuries old, and enduring."
One shop featured is Berl’s Brooklyn Poetry Shop which is New York's only all poetry bookstore. The shop describes itself as "a bookstore that sells poetry books and chapbooks; A space that celebrates art, creativity, performance, and the handmade, and a partner to many small presses local to Brooklyn, around the country, and worldwide.
Are there any poetry shops in your town?