Like I said, quality of food varies. No matter where you are that is true, not every restaurant is the same.
I’m not sure what you mean about the quality of dairy? US milk, eggs, and cheese are no different than any of the milk, eggs, and cheese of the same variety anywhere else in the world I’ve been.
There is huge variation in Dairy! French Milk (was) terrible, only UHT widely available, though fresh is now quite common. US milk is nothing like as good as British milk for freshness/flavour (though the latter is subjective).
US eggs are refrigerated, as salmonella is so prevalent. Not so in UK, where they are guaranteed salmonella free (nowadays 'thanks' to Edwina Curry)
And Cheese? Really - I'm fairly sure there is no equivalent of a nice ripe epoisses widely available in the US. Sure, cheap cheddar is just like Monterray Jack, but....
I have lived in the US for 8 years, France/Luxembourg for 2 and the UK for the rest.
There is no nice ripe epoisses anywhere in the world. If you do actually want cheese that smells like feet, perhaps as mosquito bait, you can get that in the USA. (it can not be nice however) Most supermarkets will stock Limburger, kept cold and double-wrapped with foil to avoid offending the shoppers.
We also have both kinds of edible cheese, mild cheddar and mozzarella.
It feels absurd to have to keep asking WTF people mean when they arbitrarily say x in y is better than x in the US (and let’s be honest, that’s a sign it’s not, you’re just nostalgic), but what is better about British milk? And I swear if you say fresh off a local farm whole milk is better than the skim milk you bought in Walmart that one time I’m going to stab you... we are comparing apples to apples here, not apples to white water that isn’t what your mom served you as a kid.
US eggs are refrigerated, as are those in some EU countries. It’s actually variations in temperature that cause condensation and lead to salmonella, so your whole “guaranteed salmonella free” thing is, at best, crap... as long as they are consistently warm or consistently cold you’re fine regardless. And none of that has anything to do with the quality or taste.
With cheese you finally hit a point. You want Epoisses and can’t find a decent one. That is a fair complaint, but it has absolutely nothing to do with the quality of anything in the US. I want a good rich, sharp, non-waxy (“crap”) cheddar. I also cannot find that anywhere... I’m in Europe. In the US I could find one in any grocery store I walked into.
This is about variety and availability, NOT quality. I dislike that I can’t find a nice cheddar, but I’m not writing off entire countries or continents as having nothing but crap because of it - the rest of the locals obviously don’t want it enough to keep it in stock, so it’s just going to mold before it gets bought. They have plenty of other good cheeses, just not the one I’m looking for.
What differentiates the US from other countries is that you CAN, absolutely, without any doubt what so ever, find what you’re looking for somewhere. Sure Walmart and Safeway don’t have it, but there is a smaller shop or a gourmet chain that does. That... isn’t quite true elsewhere.
I’m not sure what you mean about the quality of dairy? US milk, eggs, and cheese are no different than any of the milk, eggs, and cheese of the same variety anywhere else in the world I’ve been.