Doug Sax, and possibly Mayorga, was listening to some favored 78 records. He was impressed by the presence and sense of "aliveness" heard in many of those, but not typically experienced with LPs. Upon consideration Sax realized they were recorded directly, without the intervention of a R2R master tape copy as had become standard practice with LPs. So he experimented with a directly recorded LP, and the rest is history.
That history now includes the several wonderful recommended D2D LPs in this post.