"Bokeh as currently understood is about a sharp subject surrounded by out of focus areas, the more out of focus, the better."
As you know this is not a correct definition of Bokeh, but is more of a simple very shallow Depth of Field. Nevertheless I agree this is a current definition for many, which will hopefully self correct once digital imagery gets over its growth pangs.
But it is unfair to ask for a "serious artistic or commercial genre that was about sharpness combined with bokeh" before the words existed, much less expect a prior example of "a sliver of focus at 1.2 or 0.95".
It is fair to look for antecedents and I think they exist. I would suggest that the serious artistic or commercial genre that was about sharpness combined with bokeh we are looking for is that of Peter Henry Emerson's differential combination of sharp subject and out of focus periphery. Julia Margaret Cameron's eclectic choice of focus was also in the sphere of what we are discussing. Indeed the emphasis of masses of light and dark and blurring of detail in Calotype photography, are themselves an expression of the discussion of sharpness and detail, softness and effect. Sharpness, focus, out of focus, Bokeh, and shallow focus as an end in itself are all part of the continuum of the fundamental dichotomy of photography.
"Shallow focus as an end in itself is a new phenomenon. In the 1960s Japanese photographers of the Provoke school valorised 'are-bure-boke', translated as 'grainy/rough, blurry, out-of-focus', but that was a complete look. Now people seem to think a sliver of focus at 1.2 or 0.95 or whatever denotes artistry."
I expect this is true in a narrow sense but ignores the larger picture. One could write a similar critique in 1870 about poor focus, in 1890 about no focus, in 1895 about selective focus, in 1910 about soft focus, in 1920 about sharp focus, in 1936 about complete focus, or 2115 about hyperfocus, or today about sliverfocus.