Yeah, though I've read that it's also true for the UK. I speculated in another comment that it could be from how urbanization and industrialization went in Europe, where people were displaced from traditional sources of spices and thrown into an environment where there weren't really alternatives/replacements available, and the traditions have just further atrophied and been annihilated over the generations since with fast food and ready-made foods in stores catering to those atrophied tastes and just stacking more salt, sugar, and fat into things instead of going for flavor. In other places urbanization and industrialization were more abrupt and happened in a context where spice production was already industrialized, so tastes remained largely the same and their respective fast food and prepackaged food at least tried to mimic that to some extent.

I also can't help but assume that ludicrously cheap meat was also a big factor in food becoming blander in the US, at least, because it was an excuse to be lazy and not learn to cook when someone could just throw a cheap piece of beef in a pan with maybe some salt at the most, then douse it in red corn syrup that maybe had a detectable bit of vinegar in it, and it would be palatable enough to eat even if it was bland and mediocre.

Europe has lots of its own spices and historically made very heavy use of them, particularly things that can just be grown in gardens or foraged from the woods. It's more that the traditional culinary knowledge was gradually annihilated over the past two hundred years or so (for a variety of reasons including urbanization) and now even something like "growing a few plants to season food with" is a niche thing that only enthusiasts who are passionate about cooking do instead of just the expected normal thing for most of the population to do.

I'd probably attribute the death blow to war rationing, fast food slop, and frozen ready made food, and it's probably down to cheap fat and sugar meaning the cheapest way to mass produce ready made slop was making it bland but greasy and overly sweet. But that's also mimicking historical signs of wealth in European cooking, where rich people just stuffed their faces with the fattiest foods dripping with expensive sugars because those were all expensive luxuries, while the European poor were left seasoning stews with domestically grown herbs, garlic, and onions. There's probably an interesting investigation to be made of how culinary trends went with industrialization in periphery countries and what was preserved or lost there vs what was preserved or lost in European countries, but I don't have any knowledge in that area.

EDIT: Are you referring to the cost of spices in the UK? I'm making sure I'm following what you're saying.

I nean, nowadays it's mixed anyway. I'm trying japanese cheesecake today.

Yeah, actually adding flavor to beans makes a lot of difference.