That is not my read on the post, and your point doesn't really make sense. The objective of all these activities is measurable improvement. The practical discipline in each practice session for each activity is the bare minimum to improve and every activity has it. The point of the post is that some activities tend to see consistent, linear improvement over the long term where others tend to see droughts/plateaus.

Running is a great example because a dedicated runner, even a hobbyist, can expect to see 3-5% improvement in speed/endurance or whatever every season. But no runner expects to see improvement during a single run. But the same isn't true for activities like golf or language acquisition (my own example).

Running improvement isn't actually like this, except for beginners.

First, you actually do quite a bit of periodization at the season level, so you might have a long base block, followed by a more stamina/quality oriented block, then race specific sharpening, followed by taper and an A race, and then rest. Improvement is distinctly non-linear across these phases, and you'll actually start each season fairly far behind where you were at your peak.

There are also plateau effects, where you've basically adapted as much as you can to an existing stimulus and you need to find new ways of triggering adaptation.