I’d say people here travel more (to other countries). Why not? Tickets are so much cheaper than compared to, for example, Portugal.
A return flight to New York departing on the same day is 50% cheaper if you leave from London than if you leave from Lisbon. A flight to Vienna in August costs £20. You can be in Paris in 2.5 hours by train. Brussels in 2.
I’m surprised that there is so many people in the city during the weekends.