No, of course it's not!
And what are these people comparing it to, anyway? Usually people nominate French, Chinese, and Italian as the superior cuisines, but these people aren't looking at the bigger picture - i.e. that EVERY country originally had a very limited variety of dishes available, but TRAVEL has improved the situation for EVERYONE!!!
China - It's made up of loads, maybe hundreds, of smaller countries. It wasn't ALWAYS that big!! So the traditional recipes AND the local varieties of food from MANY countries have been rolled up into the style of cooking we call 'Chinese'.
Italy - where would they be without pasta? Created by the Chinese! Where would they be without bread? They had it in Egypt first!
France - they have a good reputation for cuisine BECAUSE they've been an international hub for centuries!
ALL good 'cuisines' combine ingredients and recipes from many other countries! Therefore, British MUST have 'good' cuisine, because nowadays we have an ENORMOUS variety of ingredients - and we use recipes from all over the world!!
Anyway, there's nothing WRONG with meat or meat-pie, potatoes, and 2 or 3 veg served with gravy...!!! There's nothing wrong with fish and chips either - but it's a MUCH better world when you can eat a variety of different foods, with interesting flavours!