I agree that people have finite bandwidth but we are talking about people investing in skills that are useful for the primary function of their job. It’s the first thing to consider if you want to improve your productivity at work.
I can see why people should improve their productivity at work in the abstract, but I have to admit there isn't much tangible in it for them. They will work 8 hour days however productive they are. Less productive workers are if anything more likely to clock out on time.
Doing "just enough" to get paid is the optimal course for the majority of jobs.
Finding jobs that extrinsicly reward continuous improvement is hard, probably because rewarding continuous improvement is hard to do - measuring, expectations, reasonable demands, etc. Are not easy.
the number of things that affect your job performance are endless and it is arbitrary where you choose to stop improving. not only is it arbitrary where you draw the line, its arbitrary that you chose to optimize your job in the first place. these things are non-self-evident choices based on personal and societal feelings rooted in first-principle thinking about the meaning of existence.
"invest in your exponential job growth" glosses over some pretty significant life choices that are more important to recognize than saving 30 minutes a day at the office.
E.g. doctors spending no time to learn about new drugs and prescribing them.
Simply staying focused on work at work, solving whatever the current issues are, and going home is fine. Languages, tools, and best practices are constantly evolving, staying current is already a significant treadmill adding mastery of everything is an endless time sink.