Past research has shown that as cities get larger, people tend to walk faster. The probable explanation for this is that as cities get bigger, they also tend to get wealthier, and so the opportunity cost of not walking fast increases. In other words, people's time is worth more.
Of course, there's something naturally unsettling about this. But it appears to be demonstrably true. Here's another, more recent, study that compares pedestrian behavior in 1979-1980 to 2008-2010 for four urban public spaces in New York, Boston, and Philadelphia.
What the researchers did was use William Whyte's famous observational work from 1980 and then use computer vision to compare it to 2008-2010. And what they found was that, on average, walking speeds had increased by about 15% and that time spent lingering in these public spaces had basically halved across all locations.
These are pretty dramatic changes that speak to a different, or at least, evolving, urban life. Increasingly, we're all just atoms racing around and trying to get to our next engagement.
Now, part of this can likely be attributed to the greater opportunity cost thing. But another possible explanation might be the advent of the internet and smartphones. Could this be a symptom of our social lives moving away from our streets and being replaced by online platforms?