An old conflict between high and low in musical traditions
Since music has been an issue of consideration in music theory treatises or critical writings in papers and books, there has always been a conflict between rhythmical and metrical parameters in compositions which were perceived as part of a humble music culture and then again the higher estimated tonal and harmonic parts of a composition, which marked the holy parts of music like cultured pearls.
Middle-aged proceedings of the ancient Greek’s pitch systems to the new tonal systems should have had developed counterparts in rhythmic aspects of the old speech-bound verse-metres. But most of the time there were none of such virtual equivalents. And this should be considered as a clear result of the progress to complex polyphony, meaning a precise organizied and rather simply composed simultaneity.
The needs for a understandability of the ecclesial texts and the coordination of choirs forced the composers to care for metric claritiy. And as a consequence any search for rhythmically sophisticated phrasings had to be moved to figurations at the beginning or within the ending of a musical phrase.