Echo chambers lead to extremism, any kind of extremism. There are no more echo chambers on "the right". Echo chambers aren't even limited to politics.

Reddit is an echo-chamber too. "Echo-chamber" is a feedback loop, not just right-wing feedback loops. Are you not understanding this on purpose?

I remember hearing that they are at increased of various illness. (Skimmed this: https://en.wikipedia.org/wiki/Medical_genetics_of_Jews )

At least they have verbal intelligence thing going for them, I guess. (Saying this in good faith of course)

What's efficient is our judgement, that's the issue. We don't experience new things or question ourselves if it's all a set of heuristics. You can't enjoy porn if you don't experience it anymore, if it loses its depth and emotional impact.

The results aren't "Porn makes people smarter". Do you know what else is efficient? Trauma. It's like a cached interpretation. Things = bad, bypassing all the calculations required to get there.

I like the idea, but I think society is re-discovering the same few problems again and again. The hedonic treadmill seems relevant here.

That we pay smaller prices, i.e. invest ourselves less in things, is a valuable observation though. Worse working memory, half-assing engagement, laziness, nihilism and the destruction of value, these all seem related.

The other factors have already been answered. If we consider where were are as 0, and where we want to go as 100, then we're always behind. Worse still is to consider the place we want to go as 0, because then we're in minus. In reality, what we have already is valuable.

Enjoy the process towards a goal and you'll have fun, enjoy only the goal and you'll suffer.

Another problem is literally getting used to things. This is solved in "The book of Est". Also partly by mindfulness, which observes rather than categorize every sensory impression into old models, so that everything is merely parsed (recognized as a hashed value), preventing change and novelty. The biggest sign that a thing has been reduced to a symbol and parsed is that you cannot reverse it. You can recognize a word when you hear it, but can you remember it if without hearing it? If not, that's a one-way association.

For the sake of efficiency, the brain might reduce all of live into a stream of familiar symbols, and discard anything which doesn't fit as "wrong". And you end up with a nihilistic person who is unable to change his mind or see value in things.

50% my own thoughts, so I don't have any more sources for you

I feel like any controversy is easily fixed by adding a "If the intrepretation of the re-worded version conflicts with the original, then the original intrepretation will take precedence" clause.

If the change is purely visual, and changing things for less offensive-sounding synonyms, then it's not really a change at all.

I think it's a silly use of man-power, but a harmless one which is (ideally) a purely visual change

I imagine that there's also advantages to be found somewhere in these genes, so that it's a tradeoff

Possibly, but apparent stupidity might be wilful ignorance or intellectual laziness. Intelligence alone doesn't guarantee any of the pleasant things that you associate it with. Even smart humans are just humans, and humans are stupid