Languages used to be so much more fluid before the invention of printing. Now printing and primary schools have slowed the process down considerably, as well as destroyed a lot of smaller dialects that never made it to printed literature. Same for gender dialects, I presume.
You could argue though that printing and schools are part of the human evolution.
True. Irish in its heyday had four rather different dialects, but today only the artificial compromise "fifth province" amalgam is taught in schools.
Same with Japanese. There are some proudly, stubbornly distinct phrases in Kansai-ben and other regions, but the choice of the Meiji-era government to only teach Standard Tokyo Japanese in schools has had the desired homogenising effect.
Even as recently as the 1940s, there are well-documented cases of teens from the south of England, sent to the north of England, to work in mines for the war effort, who simply could not understand the variety of English being spoken around them. Radio and TV smoothed out all those differences.
Language death has nothing to do with fitness, and these languages are not being "selected against" by the presence (or absence) of some linguistic characteristic. Languages die out because the groups that speak them assimilate into other groups, taking on their language and culture.
Especially seeing as hugely dominant languages like Mandarin and English are so difficult to write, and one would assume that ease of literacy would contribute to fitness.
But it's selection based on non-linguistic criteria, like who's better at violence and economics. So it affects language, but it is not based in language, and thus GP's insinuation that this linguistic feature is a "bad idea from a natural selection point of view" and this is somehow related to those languages' so-called obscurity does not make sense.
For it to make sense, language replacement (which is an observable phenomenon) would have to happen by communities learning a bunch of different languages and picking the one that they liked best. That's just not how it goes. You learn a new language to speak with new people that you're interested in, regardless of how weird and hard to learn their language is.
Indeed. English is as dominant in the world as it is today probably because England and the USA have (or had) plenty of shallow coal, iron, and (relevant after the "special relationship") oil deposits, not because of any particular linguistic efficiency.
Too late to the party with just that resource. Engines that most efficiently use oil came about only after the era of history when engines that need coal were dominant.
Fun bit of alt-history pondering - China was the most powerful single nation on Earth at the time of the dawn of the industrial revolution - it's quite plausible that they missed out on that lead just because of a couple of shallow whitewater sections of the Yangtze river that made bringing their coal by barge to the coastal cities impractical.
No, they missed out on it because of bureaucratic stupidity.
There was a Chinese industrial revolution in, IIRC, the 1100s and/or 1200s. They were producing something on the order of 100,000 tons of iron a year, with the whole industrial revolution "using the outputs to improve the efficiency" cycle starting to happen.
And then the bureaucrats shut it down, because "the wrong kind of people" were getting rich from it.
They could have owned the world. They could have been the ones with the technological and manufacturing dominance. And instead they threw it away to keep their society stratified in the way they thought it should be. The Chinese "century of humiliation" was caused by that decision back in the 1200s.
Judging the quality of something primarily based on its prevalence is a questionable idea as well (no offense). The better argument could be that some of these languages are the result of violent conquest, the subjugation of (indigenous) women and children, and possibly also of the scarcity of meaningful communication between genders.
