Time period?

It does have a lot of those vintage aesthetics like the film stock, retro book covers. But Elizabeth Moss uses a modern camera and they don't try to hide the modern cars driving around Philip while he rides his bike, so I think it's supposed to be one of those timeless pieces or the characters are all twee retro NYC douchebags. Maybe the latter.

Thematically it is necessarily retro, while the setting is contemporary. I say that because Philip's lifestyle is decidedly a thing of the past. In a modern context, there are no writers who drift effortlessly with enough success to enjoy the carefree and relaxed lifestyle that Philip has. I think thematically this would have been before my time, perhaps in the 60's or before.

At the start, we hear how Ike, in the past, published a lot of books in the 80s. I'd suggest 90s or early 00s is the era, but intentionally ambigious.