What can be said about the use of carbon steel in a commercial brewery relates more to minimizing down-time and avoiding system maintenance rather than it's affect on beer flavor.
I will grant you that no brewery today would intentionally build a system based entirely on carbon steel components. Remember, that we don't have to go too far back in brewing history to a time when mash-tuns, kettles, and fermenters were constructed of wood, stone, copper, brass, vitrified carbon steel and other materials. Those breweries brewed good beer in spite of this fact.
Modern materials like SS in today's commercial breweries have made reduced maintenance, operational efficiency, and yes quality control, better than in the past.