Just out of interest. What's to stop some other guy coming along and patenting it, then unleashing lawsuit city on all the other vendors? Is there some kind of protection for that, to assure it remains free to all?
The term "prior art" might be US-specific though, other countries' patent law systems have different words for the same thing (wikipedia suggests "background art" and "state of the art").
Not strictly right but close enough, better (but still not the whole story due to US differences) would be "things which have already been made public".
Prior art is the globally recognised term. It means any [relevant] disclosure prior to the priority date of the application in hand.
As an ex-patent examiner (not US) I'd use "background art" to represent the general status of the field (often presented in the preamble of the specification) and "state of the art" is strictly the whole gamut of prior art disclosures.
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most jurisdictions have first to file whilst US has a "first to invent" system
Although in the US you could patent the concept of a particular type of clothing being made from polartec, or even a method of selling it.