It's personal choice insofar as you need a job and your salary dictates where you can afford to live.
Complete nonsense. By your own rationale, people resident in Yourkshire and lancashire but working in London do so because wages in Lancs & Yorks are not enough to live on. Salary in the UK dictates your lifestyle noty your ability to live. How many people on this forum have taken a new job that required greater travelling distance but better prospects and financial rewards ?
"Relatively local" varies a lot. In the South East people spend a lot of time commuting, more than we do in the north.
The stats available contradict what you say. Latest studies state average commute is 77 minutes per day which is 13 more minutes than the UK average. Particularly given incoming intercity arriving before 10:00 are typically full by the time they get south of Birmingham or West of Reading or North East of Chelmsford. Going in the opposite direction they look like a ghost train. The reverse occurs after 16:00.
The thing is that Londoners are always telling me how there are so many great things in London but they never go to these things. I have.
So who goes to these events? Must be Expat Northerners in London? Would these be the same people who cannot be bothered to watch the Broncos when it is the best value and cheapest pro elite sport in London they would rather watch the game on TV in a pub.
Why are there so many folk from the South East living in Leeds?
The only ones I met have been people who returned to Leeds after working in London for a number of years. The others were students.
You have still not defined what you mean by quality of life. It means different things to different people.
In terms of quality of life you do realise only one city in the UK made the top 50 cities for QOL and guess which it was. No city place in Northern England made the rankings, Scottish cities made it on the list as did Dublin. In terms of infrastructure London is one of the top ranked cities in world.