Interesting. Where I work, we have a well defined scope for a sprint. That will get divided into tasks and then are assigned to team members. So I usually know what is my pipeline for next 2 weeks and it is fairly finite. Unless of course I am working on a more exploratory project where scope is not well defined. Of course people falling sick, or getting stuck in their task and needing help, and few other attributes can change that to some extent, but not a lot. So in summary, even though there is an endless supply for tasks that can be done, for the sprint, it is fairly finite.

Also I dont spend less time at work, I just use post lunch hour, and 30-60 mins throughout the day to do learning.