Q:

"As then, so now"

In last year's film "Victoria and Abdul," we see Queen Victoria's Indian manservant describing to her the delights of his homeland's mangoes, "the Queen of Fruits." Intrigued, the world's most powerful person immediately requisitions some. The fruit arrives, an offering from a subject subcontinent, and is presented in a velvet-lined box by two liveried staff. The Queen looks uncertainly to Abdul, who turns, disappointed, to his employer.
"This mango is off."
"Henry," the Queen exclaims to the attendant, "this mango is off!"
As it was bound to be. The mango is one of the few things in this world even more high-maintenance than monarchs. As then, so now: The great redeemer of South Asia's long, sweltering summer is a reluctant, tetchy traveler. (Source: WSJ)

My guess is this phrase means that "as it was case then, hence the case now". However, I can't find a dictionary definition or evidence that this is a phrase in popular use. What does it mean exactly here? Is this a case of artistic license of the author?

A:

It's not used to mean because of how it was, this is how it is now.
Instead, it's an elided form of a simple statement: as (it was) then, so (it is) now. It's just drawing a simple comparison between something in both the past and the present and saying that they are equivalent.
The use of the shorter form is a stylistic choice that is not ungrammatical but also not entirely common.
So: "Just as mangoes were inclined to go off in the past, so are they inclined to go off today." They used to be high maintenance and they still are.

