There seems to be way too much emphasis put upon the importance of the Mississippi river in the story of American music. The river was not the only way to travel and it's hard to believe that music, art and fashion was a side-effect of freight shipping.
It's more logical and well documented that the traveling entertainment groups and the start of the commercial music industry are how new music trends spread through the nation.
The paths to success of the early music legends in St. Louis are not based upon the river. None began in the South and traveled up the river, nor were the St. Louisans taught how to play jazz or blues by North-bound travelers.
A good example of early homegrown St. Louis talent would be Charles Creath. Born in Missouri, Creath was living in East St. Louis when he joined P G Lowrey's band. Traveling around the midwest in the teens, Creath and other St. Louis music legends like William Blue and Harvey Lankford spread the new sound of jass on what would later become the Black vaudeville circuit.
It's clear that the jazz legends of St. Louis did not learn from and were not influenced by the mythic New Orleans players like Oliver, Keppard or Bolden. The early music of St. Louis is groundbreaking and creative and uniquely its own. The rivers and railroads were much more important for hauling commerce than culture and the more we learn about St. Louis history the clearer it is that the Confluence at St. Louis was where others came to hear what was new.