There are various notions of "focus" in academia, many of which are associated with the "positive psychology" school.
In sympathy with your observation, I've looked for studies of these phenomena. But I haven't yet seen any study about the difference between "focus" in contexts where the agent has deeply internalized complex skills (e.g. an athlete) versus "focus" in contexts where the agent is expected to deeply internalize seemingly arbitrary routines (e.g. a warehouse fulfillment worker). Needless to say, athletes are much more able to "focus" than warehouse workers.
I suspect that it may be statistically significant that, in the athlete's case, their ability to "focus" is deeply related to how emotionally fulfilling their tasks are perceived to be.
In other words, we should expect wildly divergent degrees of "ability to focus on work" depending on the type of work we are discussing.
To me, this is the crux of the Developer Experience movement: give me meaningful work, and I'll give you inspired/concentrated labor; give me bullshit, fruitless, clickbait concerns, and I'll give you bare minimum effort.