"It" in this case is the subject of "has been", a singular verb that refers to a singular thing, "a long road", thus it's a perfect construction from a grammatical point of view. "It" here is called "anticipatory subject": it's a sort of "fictious" subject used in this kind of construction. If you note, from the point of view of the meaning, the "logical" subject is "a long road": "a long road out of the woods has been (meaning: there has been, has existed) for the American...etc. But that would be an "ugly" construction: with "it" as an "anticipatory subject" it sounds better.

In this case, "it" refers more to "the situation". For example with, "recently, it has been difficult making a living", we use "it" to refer to "the recent situation". You will see this kind of phrase using "it" very often.

"it" doesn't refer to economies to be plural.