I'll keep repeating myself: the cognitive cost of "code" is dwarfed by the cost of understanding an application. If a couple esoteric languagn features take an extra few hours to learn but reduce LOC tenfold, it's a price I'd pay every time.
Not everyone feels this way, the investment to learn these features may not pay off right away, and if you come from a "move fast and break things" language (python/php/js) it can feel like a waste of time.
> If a couple esoteric languagn features take an extra few hours to learn but reduce LOC tenfold, it's a price I'd pay every time.
Issue is that a beginner pre-conditioned long enough on "verboser, imperativer" models/languages, when reading/comprehending such a codebase, has to literally mentally expand every 1 line into 10 upon reading, for quite a while .. some weeks, some months, as more intuitive grasp sets in slowly over time. Probably what happened at OP's quoted company and with the different speeds in comprehending what "clever" (compact) code some of their coders came up with, what they flippantly called "code that was harder to understand by others"..
If a couple of esoteric language features can consistently reduce your codebase tenfold, you might want to rethink how you engineer your apps. Unless you're writing your application in FORTRAN (and I mean the version before 1958 and the introduction of procedural code) or assembly, I doubt there are any two general-purpose languages that show a 10x difference in code size in large applications.
Not everyone feels this way, the investment to learn these features may not pay off right away, and if you come from a "move fast and break things" language (python/php/js) it can feel like a waste of time.