Maybe it's an over simplification but my take is that the Catholic tradition convinced us that Scripture is mystically obscure and clergy are the ones who can explain it. I don't think that catechisms were invented to bridge any gap, but rather to relieve the Catholic from search, question, ambiguity, personal religious autonomy. In the traditional life of the ordinary Catholics priests were important. Theologians might as well have been what priests wore under their cassocks. 
I can't speak for Protestants but only refer to the quote from a congenial Minister who summarized: Catholics live under the tyranny of the chair; Protestants, the tyranny of the Book".