Opinion: as London's Barbican gallery launches a major retrospective on Modernist designers Charles and Ray Eames, Sam Jacob wonders whether it matters that the Eames name has taken on a life of its own.

Right now there are 11,085 results for Eames on eBay. Take your pick. Maybe you fancy a "Large Retro chair in faux lizard skin heals eames". Or a "Brass Gladiator Chariot Sculpture Mid Century Eames". Or a "Globe Hidden Ashtray Space Age Mid Century Modern Eames Era1960s". How about a "PIN UP & DESIGN SOEUR AURELLE Kinky Nun Stephan Saint Emett / Eames SCULPTURE", a "vintage 3 EAMES ERA MID CENTURY NATURE BOY CAVEMAN REAL RABBIT FUR" or a "Leopard Dining Chair Retro Luxury Sexy Ghost Posh Panton DSW Dressing Eames".

Kinky Nuns, Cavemen, Aztecs, Denmark, Brutalism, Regency, and Sputnik are all prefixes and suffixes to a huge homespun market of Eamsiness that falls under the banner of Mid Century – itself a vague term that lumps together a disparate array of design of a certain vintage under a saleable moniker.

Eames is no longer just a surname, no longer simply the signature of the design couple and the denominator of a specific body of work. It's become a hazy, vaguely suggestive word: an adjective rather than a noun.

Eames – outside of the world of design scholarship and commercial licenses – has become a word applied to alchemise junk shop remnants. A word whose prefix-polish transforms the value of the object to which it has been attached, a kind of culturally magic Brasso intended to bring out particular qualities in an object, even if those qualities aren't there in the first place.

It's a word that – in this space of internet bring-and-buy at least – has escaped all sense of its original origin. As if it had wafted out of the studio through an open window out into the world, its meaning atomising and spreading like a toxic cloud till some homeopathic remnant of its original particulates have contaminated the entire landscape. "Eames" is a gas cloud, a powerful atmosphere that has the power to Eamsify anything it touches.

These eBay phrases are also absurd, like surrealist word games or the kind of spam-language generated by algorithms to evade filters. Phrases that, against our expectations where words have some relationship to meaning, are a garbled babble that could never mean anything at all.

Of course this all happens outside of the policed official legacy of the real, original Eames. Outside of the worlds that cling on to values of authenticity, attribution, and legitimacy.

Yet there is something strangely authentic about this junk-shop phenomenon, something oddly Eames-like about its fake Eamesiness.

Junk shop Eamesification is the contemporary and vernacular equivalent of the openness of Charles and Ray's own design spirit. The world of the Eameses was one of high design of course. But it was also a world full of vernacular stuff, of folk objects, tin toys and all the rest. Ordinary, non-designer things that they arranged to create new suggestions of how the world might be designed.

And it was this – as much as anything they designed – that was so admired by European architects and designers. That relaxed easiness, bathed in the sunshine of California, must have seemed so exotic, so far removed from post-war austerity of, say, Alison and Peter Smithson, that it must have seemed like the future. The Smithsons wrote "the Eameses have made it respectable to like pretty things" – a pretty shocking admission for architects steeped in a rebooted, fundamentalist take on Modernism.

The Smithsons admired too the Eames ease, the fluidity between lifestyle, personality, image and design practice, writing that "Charles Eames is a natural Californian Man, using his native resources and know-how – of the film-making, the aircraft and the advertising industries – as others drink water; that is almost without thinking."

And in a sense, this is the real legacy of the Eames: their synthesis of image-making, lifestyle and design. It was an attitude towards the role and meaning of design that could only have been forged in the specific circumstances of mid-century California. But it simultaneously invented an idea of California as a design project. It's impossible, I would argue, to imagine the possibility of the phrase "Designed In California" that adorns Apple products without the Eames. Through attitude – perhaps even more that the work they produced – the Eames shaped the landscape of contemporary design.

As the Barbican Eames exhibition opens, we could imagine another show – a shadow show – with the same title. A show made up not of their work but of eBay Eames objects, of Brass Gladiators, Kinky Nuns and NATURE BOY CAVEMAN. Because just as everywhere is California now, everywhere is also the world of Charles and Ray Eames.

Sam Jacob is principal of Sam Jacob Studio, professor of architecture at University of Illinois at Chicago and director of Night School at the Architectural Association, and edits Strange Harvest.