There’s this meme from a while ago that observes the fact that the 80’s and early 90’s weren’t as colourful and flashy as most media make them out to be. In fact almost everything ranging from clothing to furniture to advertising was a drab shade ranging between dark brown to orange.
Every once in a while you’d get a toy or a household appliance that would be a bright neon colour and it would be considered hi tech advanced fancy stuff (until it broke the next day).
Nowadays you’d have to look hard for dark brown/orange drab stuff. They make dark brown/orange stuff but it usually is made of a veneer of fancy wood and it’ll cost you an arm and a leg. (And then it breaks the very next day)
I was a teenager in the eighties. I remember a "jungle" trend (khaki), purple paisley, bottle green, grey with abstract prints, light pink and grey t-shirts with the sleeves cut off and lapis blue. I have NO idea where the idea of "it was all neon" comes from.
The idea comes from the fact that there's multiple concurrent trends at any given time. But also the BTTF posters. Also consider how the monochrome movement made neon stand out even more than it did during the vibrant 60s and 70s. And yet, all of this varies greatly by region. We're all seemingly assuming USA, so an NYC/LA experience will not match Birmingham or Dallas