Such things aren't choices in any conventional sense of the word - they're package deals, and you don't get to renegotiate the package. You can live in London for the opportunities and culture, but you can't easily escape the crime and traffic pollution.

That's true, but I think that's an overlooked factor in some other "lifestyle choices" as well. For example, people who significantly reduce their alcohol consumption often report changing social groups and activities to do so, so in at least some cases it can be a package deal. I don't think there are very many choices that are completely isolated, independent from all other choices, and free of consequence on any other aspect of your life, though there's definitely a spectrum of being more or less so.

I'll agree it isn't a lifestyle choice in the conventional sense of the word. But I personally think each person should individually strive to make it so. Mobility is hugely underrated. And some packages are better than others.

And it's illegal or impossible to leave London? You can't renegotiate the package, but you can always choose a different package.

Perhaps, but the health benefits may be outweighed by moving from a city with a large economy out to the country where you'll have to subsistence farm for a living.

You are confusing the UK with India and China.