For your consideration, a theory about the curious intersection of music, film, and the passage of time, courtesy of Steve Haden at the AV Club:

…director Robert Zemeckis used Lewis’ “The Power Of Love” in the biggest box-office grosser of 1985, Back To The Future. Conceding that I was likely giving Zemeckis and his co-screenwriter Bob Gale too much credit, I argued that “all the timely accoutrements signifying ‘the present’ in Back To The Future”—including denim jackets, Calvin Klein underwear, Tab soda, and Eddie Van Halen references, as well as “The Power Of Love”—“would inevitably look like 1985 within just a couple of years; in fact, they were banking on it. Zemeckis and Gale were trying to create an archetypical representation of 1985 just like they did for 1955, with its soda fountains, social repression, and subjugated black people.”

In essence, I was asserting that Back To The Future was “a period piece made in 1985 that depicts 1985 as an era as distant-seeming as its version of 1955.”

I agree that Zemeckis and Gale probably weren’t consciously trying to peg BTTF into instant period piece status with their choices for art direction and soundtrack (its just too precient for mere mortals to accomplish on purpose), though looking back, damn if they didn’t manage exactly that.

I’ll take Hayden’s theory one further, positing that he same sense period piece logic be said for the other less-current eras represented in the trilogy, though with an added wrinkle: unlike 1955, during which at least some of the films’ contemporary audiences were alive (even if their recollections of the time period are colored with nostalgia), nobody watching had any practical experience with life 100 years in the past or 30 years in the future. As such, to maintain the indelibly pegged to 1985 feeling, the films likewise extrapolate the past and future eras through the films’ more current eras’ pop culture lenses.

Hill Valley 1885 is exactly the kind of polished, black & white, and just a little steampunky Wild (Wild) West kids watching TV westerns in the fifties (or watching the re-runs 30 years later) would imagine. The grim-and-gritty westerns like “Unforgiven” hadn’t been invented yet (let’s leave out the gratuitous ZZ Top cameo for the moment). In 1985 popular parlance, the western setting was “Gunsmoke” or “The Rifleman,” and didn’t get any darker and murkier than The Man With No Name.

Likewise, sitting here in 2011, the vision presented of the year 2015 with it’s hoverboards and shiny robot waiters is clearly off the mark, but it’s exactly the kind of future a mainstream kid in 1955 or suburban 1985 would imagine. Sure, by 1985, Gibson had written “Neuromancer” and Ridley Scott had already given us “Blade Runner,” but the former was still a small little science fiction novel, and the latter was arguably still considered a flop; neither had yet had enough time and distance to let their dystopian influence be felt on pop culture’s vision of the future…to rank and file america in 1985, the fifties vision of atomic future utopia still largely held sway.

In any case, I don’t imagine that the filmmakers consciously crafted their vision of an archetypal 1985 with popular references that they imagined (correctly, it turns out) would mark it as immediately dated, though when crafting their images of the distant past and future, they considered the pop culture of the eras of the characters’ (and thus the audience’s) pop-culture infused recollections and experience when designing those images. While neither 1885 or 2015 are represented (or extrapolated) particularly accurately, to the audience watching the films in the mid to late 1980s, they “felt” right based on collective cultural experience, and arguably, that’s what made the films effective.