“The Lost Arcade,” a documentary elegy for the dearly departed Chinatown Fair of old, takes an important place in the cultural firmament even if it fails to make a persuasive case that the Mott Street institution was a place truly worth mourning.

The picture poignantly illustrates how much the dilapidated old storefront meant to its regulars, employees and former owner, and it offers a tribute to an arcade culture long since lost to the world of home consoles and, now, smartphones and tablets.

Happiness in New York City, as vast and imposing a place to live as any, depends on establishing and maintaining the sort of micro-community built by the Chinatown Fair regulars, until it closed in its original incarnation, only to be reborn later as a more antiseptic and “family-friend” locale, an iteration that continues today.

Still, there’s an arbitrariness about this particular subject that’s drawn out when documentarian Kurt Vincent tries to make larger, sweeping points about the decline of this broader milieu.

There are arcades everywhere in this city — the Barcade franchise, Dave & Busters, Coney Island, to name just a few — and plenty of indications that this world is in fact alive and well, albeit mostly more corporate and less grungy.

It’s hard to feel too emotional about any of it, for that reason.