I think this is true of many mass marketed packaged products and has been for decades - sugar and salt drives the flavor, vs having properly rendered cooked foods. Many people may still reach for that box or packet of sauce though because they don’t have alternatives to make from scratch or aren’t confident about their skills. I personally think Trader Joe’s prepared foods (frozen and fresh) skew sweet, as do some of Costco’s prepared meats (their bulgogi pork/beef was so sugary I couldn’t eat it).
Eating at non-fast food restaurants themselves - other than clear adaptation of flavors to locals (i.e., non-Asian audience) - I can’t say I see this in a lot of restaurants either. I do think the reverse import of some flavors that are non-traditional back into the native land happens, and I wonder if that is what is being seen with sweet Korean chicken flavors or HK foods and flavors. As consumption of global foods rises, there are also a lot of entities moving traditional hand-made foods to machinery and mass production, and I think this drives the taste change just as much too, rather than a growing or evolving sweet tooth.
