We can try to sort it out as social development in what we call Music History. But for a composer it is still very confusing, all the more so because we learn music from the early stages of life, and absorb along with the beauty and delicacy of the music of each century the formal characteristics of the music of that age. Step by step we move through the jumble of time and into the morass of a musical ROM, remembering every detail in our unconscious mind, until we begin to invent our own voice, our own sound, under the burden of a long past. As workers move better to a chantey, or soldiers march to a drum or song, so dancers need a beat for their feet. Rock, Country and Jazz music still lockstep to the beat in the measure, creating the symmetrical sound to which our society is attuned.
Instrumental ensembles have the problem of all the voices sounding together.
If you are going to have Harmony and an orchestra, you have to synchronize. Recordings in the last fifty years have become increasingly firm about exact timing, often to the extent of sounding mechanical. Or consider the way Casals played the Bach Cello Suites, with their subtle and meaningful off-time variances. One wonders why we have become so mechanized. It is not just in popular music, but everywhere there seems to be a need for the Upbeat and the Downbeat in every Measure.