I'd think it would be obvious: London is the closest thing we have to a planetary capital, and has been such for 250 years. Here in one spot: a major government with world wide connections; one of the three and sometimes the foremost finance center on the planet; a huge and diverse population; access to some of the oldest best and most advanced centers of education, research, and technology on the planet; in relative terms, quite close to all significant places save those around the Pacific; equidistance from the west and east sides of the Pacific; and by far the largest city in one of the three world super-powers, Europe. London also has a cultural life and a history as rich/long as most any inhabited spot.
Besides, I love it there. Parks plays museums great transit great shopping marvelous neighborhoods to explore, to walk, places to eat to drink to socialize. The real food of all the planet's peoples. And wild and solitary places within a travel time of a few hours.
The weather...let's not talk about the English weather lol. But then the central valleys of California actually would be uninhabitable at least most of the year, but for vast amounts of imported water and energy, the weather there is imho world class awful, and so is the air.