Best not to conflate all bread in America with Wonder Bread. We have bakeries that actually choose to make a quality product, and it's available in (edit: grocery stores in) most cities. Many Americans simply choose to optimize for cost.
Having to go to speciality bakeries to get good bread is a different thing than just having it available in every corner market and whatever the bodega equivalent is.
But you don't have to go to a specialty bakery to get good fresh bread. I can get Acme Bread at nearly any grocery store in the San Francisco Bay Area -- and lest someone (fairly) say, "Yes, but that's the Bay Area," anyone who grew up in the southern US probably knows Publix, the biggest grocery store in that region, is justifiably famous for their in-store baked breads.
I think there's sometimes a tendency among Europeans in particular to write off all American food as being essentially the same as the most iconically awful brands we have over here: Wonder bread, Velveeta cheese, Hershey's milk chocolate, Bud Light beer. And that's just not true.
I'm sort of inspired by Vox's article on the "boring lunch" here to start packing simple sandwiches again, which I haven't done in years. If I do, I'm probably going to be able to get pretty good bread, butter, cheese, and meats -- they're just not that hard to get here.
The difference is that when I lived in Florida I was going grocery shopping at Publix once a week or so. I tended to buy in bulk and prioritized shelf life. I now live in the downtown part of a walkable city and I tend to buy staples every other day or every 3 days because I can just drop in on my way home from work.
Having the good stuff suffusing your daily life rather than being a specific thing you need to go get makes a difference in your relationship to the food. It’s just easier. It’s not a decision you make, it becomes a default thing you get.
You don't need to go to a specialty bakery to get good fresh bread in most of the US. It is ubiquitous in most cities, and many stores that sell it will start to run out later in the day. It is either made or delivered daily. Several small shops within 1-2 blocks of where I live all sell fresh bread.
The old school sliced white loaf in a bag that was very popular in the 1960s has been in decline for at least a few decades. I rarely see it anymore.
In my experience most of the food is. American seem to go for quantity over quality. I am sure there are exceptions (they do good hamburgers) but most of the stuff i got served seemed overly processed.
