British cuisine was not that great but has improved immeasurably over the past 40 years. After the war rationing continued for ten years and crippled what cooking ability we had. With no fre4sh eggs, 4 oz of meat a week and even bread rationing at one point we Brits weren't able to do much in the way of haute cuisine.
In the fifties cooking in UK went two ways. One was the US way of convenience food and instant coffee and the other was led by pioneers such as Elizabeth David who introduced us once more to the cooking of France and southern Europe. When I was a kid in the fifties I had never seen an eggplant, a capsicum or a zucchini (I us the US name so that Americans and English both know what I'm talking about). We still have the two sides to our cookery but the foodies are making inroads.
TV chefs like Rick Stein have done wonders to let us know where we can get quality food. Our traditional cheeses have been revived (after the war only factory cheddar was available) and we also have new cheese made by local farms. Just try a Shepton Mallet cheddar and compare it with factory stuff.
We've also become more international. Our national dish is now reckoned to be curry and the balti curry is a curry born in Uk created by our Pakistani origin immigrants. Indian and Chinese restaurants started with cooks who had really rather little knowledge of their own cuisine and tended to cook in a way that they thought the locals would accept but now we have some very excellent ethnic restaurants.
We travel more than US residents and although some Brits aboard insist on chips and "food you can recognise" ( restaurant advert seen in Corfu in the 70s) many have enjoyed foreign foods and have returned from holiday to create them themselves.
So we have more interest in traditional Brit food, seeking out the best traditionally smoked kippers and cooking traditional Lancashire hot pot with oysters. We have an immigrant population who have spread knowledge of their cuisine and we have a well travelled population who are more sophisticated in their tastes than previously.
Sure, the tomato ketchup slurping TV dinner fans are still there but I can usually find pretty good food whenever I go back to UK. Just go to somewhere like Borough Market in London and see what we have to offer.
I don't know the US and US exports to my home town, Hong Kong, tend to be fast food joints and steakhouses. We don't get very good US food over here, just places that do oversized portions of fairly plain dishes. Australian cutting edge restaurants are much better if you want western food in HK. I am sure that US has plenty of good food other than the mass produced factory junk and hormone stuffed meat but it doesn't travel.
I think you have to compare like with like. US and UK factory food is pretty disgusting but there is good food in both places. Fifty years ago our food was pretty sad and London was beset by smog. We've changed and I think we are in some ways better than the US. One of my US colleagues was amazed to find that there were 2 kinds of tortilla