Not to be that guy/gal, but if work isn’t being completed on time, this could actually just be a lazy person who is purposefully putting in little effort. No amount of training is going to fix that. When I managed folks, if you were at the bottom of pile regarding amount of work you completed in the same time as other colleagues, you were offered training (which involved repeating things folks already knew) or you were counseled out - either way chances are you don’t/didn’t like the work, so why continue being miserable. Why should I keep paying the low performer, when I can just use that training time for a new employee who is willing to put in the work. You can make the argument that it is costlier to hire new employees, but the toll low performers take on the moral of the rest of team isn’t great either. How would you feel knowing that someone who puts in 30% of your effort, gets paid similarly (granted performance based bonus and raises are highly variable)

Also read the article. It has absolutely nothing to do with someone having too much work to do in a small amount of time. She even admits she mis-logged as well as claims to have been working with paper documents of which she doesn’t have any proof of.