One of the most persistent metaphors used to describe the evolution of media consumers is that they increasingly behave like drug addicts.
And while in the past, the most common addictive analogy might have been opiates -- as in an insatiable desire to want more -- these days they seem …
Joe, if half of mobile users leave a website that takes more than three seconds to load, what's the corresponding number for half of all digital users? Certainly it's not 8, as shown in the table. Maybe, the fastest departing half of all digital users leaves in 5 seconds? Another question that might be asked is this. If mobile accounts for 65-70% of all digital media activity and its least attentive half will spend only three seconds waiting for a website to load before going elsewhere how can it be that the average wait time for all digital usage, including mobile, is eight seconds? Are some people waiting for ten or twenty seconds in order to produce that "average" figure of eight seconds? I'm not questionning what you wrote regarding decreasing attention spans---but the data shown in the table raises some questions.
https://www.bbc.com/news/health-38896790
The first mention of shrinking attention spans was via Microsoft in 2015. However, research that followed up found attention span duration is highly dependent on tasks and context.
BBC article above presents the counterpoint.