Why Don't We Know About this Music?

     "It is a strange though incontestable fact that of the immense treasure of baroque music, only certain compositions in late baroque style have succeeded in finding a permanent, if subordinate, place in the present-day musical repertory and that, as a consequence, the characteristics of late baroque style are commonly mistaken for those of the baroque as a whole. It would be wrong to explain this preference by contending that the late baroque masters were "greater" than their predecessors; this interpretation would only confirm the lack of familiarity with the previous periods of baroque music. 
     "The reason lies deeper than that. Late baroque music does indeed differ from that of the earlier phases of baroque style in one important respect: it is written in the idiom of fully established tonality. After the pre-tonal experimentations of the early baroque and and the use of a rudimentary tonality in the middle baroque period, the definitive realization of tonality in Italy about 1680 marks the decisive turning point in the history of harmony which coincides with the beginning of the late baroque period. It is precisely the use of tonality in the late baroque that connects this period more closely than any other with the living musical repertory of today."

Manfred Bukofzer from Music in the Baroque Era