Couldn't fit the title I wanted but it struck me watching what I'd call bluegrass (and it's precursors) on YouTube that these bands seem almost entirely string based (fiddle, banjo, guitar etc). Many other traditions in USA (and Canada for that matter) use diatonic accordions (Cajun, Tex-Mex etc).

Are there any reasons why bluegrass didn't adopt the diatonic accordion (difficult to acquire/make, cultural reasons)? Just a curious melodeon player from England