Even the Aldi, known for having just a single option for everything, has about 15 different breads.
I'm sorry if your options are bad, but don't claim that the entire US sucks.
Let them eat cake.
P.S. But I do like the sourdough and rye bread (uncommon in UK).
You can also just go to a bakery. Not sure how accurate this site is, but it looks like the US and UK have about the same number of bakeries per capita. https://www.ibisworld.com/industry-statistics/number-of-busi..., https://www.ibisworld.com/united-kingdom/number-of-businesse...
Certainly there are some places where your only option is a dollar store that probably won't have anything good, but I've been a lot of places in the US and I've never found this to be an issue.