Mississippi has far better food and better weather so I don't think life is better in the UK. Also, I have no idea where you got the life expectancy number from, but its not current. I suspect its just a bit old. Its currently like 74 and mostly that's the effect of the Oxy epidemic which is going away with time.

I have been to the UK and I have been to Mississippi. Quality of life in Mississippi is far higher unless you really really like musicals (London is big for those). Mississippi has a better history of music and writing over the last 100-150 years. The food is cheaper and far more tasty. The weather is warm and winters are mild. They generally don't get natural disasters unless you live right by the coast and even then its once in 70 years. The health care is far higher quality. The people are warm and friendly. And the cost of living is lower.

The British are known for being miserable for a reason.