That misses a bit the point of the article IMO: That some "horns" have a threshold beyond which the standard diminishing returns formula is the wrong way to think about it, and that once this threshold is crossed you open up a whole slew of new parameters to toy with, as if you'd just started on something entirely new (which is often the case in some sense).
For instance, you can learn more and more about the rules of poker (to take a very limited field which runs into diminishing returns very fast) and quickly exhaust everything there is to learn... until you master them so completely that suddenly this whole new thing opens up about counting cards and deception, which is somewhat a different thing not directly about the rules of poker but an implication of them, which upon further analysis reveal why certain rules work certain ways or why certain rules are of key importance.
Then, once you completely master that, you get into this whole thing about probabilities and game theory and abstract up into the metagame with agents simulating other agents' simulations of you... but that's a bit beyond my own level of understanding, to be honest, so I'll cut the example short here.
Basically, the guy who stopped trying to learn more about poker rules because he saw diminishing returns and never pushed forward enough to "get" the things that lead to counting cards and deception and metagame will have missed out on the point of poker entirely.
At least, if I'm interpreting the main article correctly, there are some fields of knowledge which behave in a similar fashion, and we might benefit from having good heuristics for figuring out which fields will behave like this so that we can improve our research efficiency... or something.
That some "horns" have a threshold beyond which the standard diminishing returns formula is the wrong way to think about it, and that once this threshold is crossed you open up a whole slew of new parameters to toy with, as if you'd just started on something entirely new (which is often the case in some sense).
(paragraphs 1-2) This idea that there's a transition point where suddenly returns start increasing appears nowhere in the physical instance of a powder horn (when you finally turn it over, do you get even more powder than your first easy...
Some time ago I learned of the metaphor of 'digging the bull's horn'. This might sound a little strange, since horns are mostly hollow, but imagine a bull's horn used to store black powder. In the beginning the work is easy and you can scoop out a lot powder with very little effort. As you dig down, though, each scoop yields less powder as you dig into the narrow part of the horn until the only way you can get out more powder is to turn the horn over a dump it out.
It's often the same way with learning. When you start out in a subject there is a lot to be learned (both in quantity of material you have not yet seen and in quantity of benefits you have to gain from the information), but as you dig deeper into a subject the useful insights come less often or are more limited in scope. Eventually you dig down so far that the only way to learn more is to discover new things that no one has yet learned (to stretch the metaphor, you have to add your own powder back to dig out).
It's useful to know that you're digging the bull's horn when learning because, unless you really enjoy a subject or have some reason to believe that contributing to it is worthwhile, you can know in advance that most of the really valuable insights you'll gain will come early on. If you want to benefit from knowing about as much stuff as possible, you'll often want to stop actively pursuing a subject unless you want to make a career out of it.
But, for a few subjects, this isn't true. Sometimes, as you continue to learn the last few hard things that don't seem to provide big, broadly-useful insights, you manage to accumulate a critical level of knowledge about the subject that opens up a whole new world of insights to you that were previously hidden. To push the metaphor, you eventually dig so deep that you come out the other side to find a huge pile of powder.
The Way seems to be one of those subjects you can dig past the end of: there are some people who have mastered The Way to such an extent that they have access to a huge range of benefits not available to those still digging the horn. But when it comes to other subjects, how do you know? Great insights could be hiding beyond currently obscure fields of study because no one has bothered to dig deep enough. Aside from having clear examples of people who came out the other side to give us reason to believe it's worth while to deep really deep on some subjects, is there any way we can make a good prediction about what subjects may be worth digging to the end of the bull's horn?