The disappearance of true soy sauce would be a real tragedy - it sounds magnificent. Interestingly, it seems that other authentic flavors, like Balsamic Vinegar, are produced in much the same way - with authentic wooden barrels, aging over many years - and that what's sold in the mass market is rushed to market as quickly as possible. For authentic Balsamic Vinegar, the same time-tested methods apply:
In order to be labeled Aceto Balsamico Tradizionale D.O.P., it needs to be made in Reggio Emilia or Modena, Italy, and produced using the following method: First, grape must from local late-harvest grapes (usually lambrusco or trebbiano) is boiled down until it’s reduced by half, left to ferment naturally for a few weeks, then matured and concentrated for a minimum of 12 years. It can’t just be left in a cask like whiskey, however: During this time, the reduction is gradually transferred through a series of at least five progressively smaller casks, each usually made of a different type of wood so the resulting product picks up each complex flavor. The vinegar in the final cask is rich, dark, viscous, glossy, and concentrated, due to the evaporation that occurs over the years.