I was in central London yesterday at lunchtime observing the office workers getting lunch. And not a single non flat shoe to be seen. Mostly the trainer and dress combo (all sorts of dresses and all sorts of trainers), also as its summer flat sandals. Same at the all-female conference I attended including all the speakers.
I've always been mystified by very high heels as they tend to look more unattractive than attractive as the wearer hobbles down the street like they've been hit by a car but think lower heels can look nice and add a bit of height and style. Clearly most people are not prepared to put up with uncomfortable shoes now.