I see they repeat the myth about a great developer being ten times as good as a mediocre one, even though the actual reference they point towards in support of that statement disagrees with them.
The speed improvement isn't like, "This person can type 10 times faster than everyone else", but more like, "This person doesn't get stuck or waste time chasing dead-ends".
Possibly your code-base needs to have more than a certain level of complexity before developers start getting stuck like this.
I've been in similar situations and, invariably, the "few lines of code" is inscrutable nonsense that no-one else will be able to maintain (and often even understand.) I can write obtuse one line "clever" hacks to solve problems but I'm keenly aware that a) I'll have forgotten how it works in an hour and b) some poor bastard (which might well be me) will have to maintain it for N years after I'm gone.
Presumably this was a trivial data dump and not something like a report that could have benefited from, e.g., embedded formulas, multiple sheets, etc.? (I've produced exports with the latter and the enhancements were greatly appreciated over the plain old CSV export.)
For example, it is impressive how much code can be simplified by just using the correct API calls. Also, some language features are explicitly designed to address a specific problem, and yet they stay unused, even when the problem arises.
As for your two points.
- If you forget about how it works in an hour, you never knew how it worked in the first place. It can happen when you write code at random and tweak it until it passes the test. IMHO, that's the opposite of a clever hack.
- I love to see clever hacks in code I maintain. Like everyone else I start going "WTF?!" but a few minutes later, it usually turns into "oh nice, I learned something today".
To illustrate, this is the kind of code I like to read https://www.youtube.com/user/Bisqwit . This guy's code is short, clever, takes advantage of everything the language has to offer, and still manages not to be too cryptic. Note that these are educational videos and the author spends a lot of time to get to that level. I don't expect to see that in a typical project, but that's kind of an ideal for me.
Obviously I disagree. I'll have forgotten through a combination of being old, not being interested in that code any more, having spent an hour doing something else, and work not being important enough to take up rent-free space in my brain.
It wasn't a hack, so much as removing someone elses (unnecessary) hack that fixed the problem.
A 2nd edition of Peopleware summarises it; the 10x programmer is not a myth, but it's comparing the best to the worst; NOT best to median. It's also not about programming specifically; it's simply a common distribution in many metrics of performance.
The rule of thumb Peopleware states is that you can rely on the best outperforming the worst by a factor of 10, and you can rely on the best outperforming the median by a factor of 2.5. This of course indicates that a median developer, middle of the pack, is a 4x developer. Obviously, this is a statistical rule, and if you've got a tiny sample size or some kind of singular outlier or other such; well, we're all adults and we understand how statistics and distributions work.
Peopleware uses Boehn (1981), Sackman (1968), Augustine (1979) and Lawrence (1981) as its sources. [ "Peopleware", DeMarco and Lister, 1987, p45 ]
If I think of it as team dynamics, I can see a single developer making that much of a difference. On his own (s)he is not that much better than your average developer, but in a team (s)he can lift the team with his/her experience and really make them significantly better. 10 times better is probably a stretch, but measurably better at least.
I think the key is to actually care about your work. You got even a little bit of that and you're fine.