its really pretty simple to understand
They buy the cars to get that attention, not because they actually enjoy their cars themselves that much.
For them, its all about showing off your wealth, impressing people, making people look, all whilst socializing with their friends, and enjoying the eating out and drinking london has to offer by night and shopping in shops they don't get back home during the day.
All whilst escaping the searing heat.
If they were actually genuine petrol heads, they'd probably spend their summer at the nuburgring.