If they dived deeper into the usage patterns and broke down app usage by specific apps, I'd suspect a vast majority of that time is spent in a tiny handful of popular apps, since there are also countless studies pointing to the fact that consumers don't install more than a handful of native apps.

If you remove time spent in those popular apps and their respective websites from the stats, the data would likely paint a vastly different story (that might not be in the best interest for a site that relies on pushing "Launching mobile apps for your WordPress site" to highlight ofc).