The frowning upon is religion based values. On the other hand multipe wives and no other husbands allowed is also religion based.
Next question would be why is same sex marriage frowned upon?

There is a reason why ancient societies were matriarchy based. It was always easy to tell who the mother was. And because of that the wealth was tied to the mother’s bloodline instead of the father’s.
If you want a real - future proof inheritance system: leave everything to the mother than as she dies the children get everything.

One on one pairing is more fair with big numbers. You no longer have to take your brother’s widow as a wife, you do not need to marry to make sure you have one extra goat to milk ar having a maid and incubator for the next generation.
Humans generally speaking do not need to make more than 2 kids. Your bloodline won’t die out because of modern medicine. Nobody’s bloodline worth anything anyway. Your genes are not that superior.

So there is no logical reason to support a one sided marriage system.
Now open polyamory where everyone is on board, equal, open about it and can leave any time - go ahead that totally green light from me.

I do not agree that efficiency is good.
If its is good, we would live like we keep pigs and chickens in meat farms. More efficient is to eat bug based protein, and why waste time on eating instead of 100% meal replacement foods.
Why keep people with disabilities or with different “colors of skin” (insert any other thing there) from the most “efficient” ones?
The best way to think is Matrix-esqe pods for humans and living in a simulation.
Only bad part of that picture is that we are not needed at all.

And these are the dark points of unlimited change.
We all know capitalism is very bad for the majority. We know big money do not care about marginalized groups. These are all just numbers. And at the end you and I we are all numbers that can be cut. I’m probably not going to be alive, but I hope for a bright future for the upcoming generations. The problem is that I do see AI potentially darkening their skies.
Don’t get me wrong AI can be a great tool if you learn how to use it. But the benefits are not going to be in the people hands.

We need a general society overhaul where not the profit is the only thing that matters. Efficiency is good when you burn renewable wooden pellets and you want to get the most out of the chemical reaction. Efficiency is good when you are using the minimum amount of material to build something (with 3x oversized safety measures). But efficiency in AI and in social terms are going to be a problem.

Humans will not have worry free lives in current society. All the replaced labor keeps the earnings in the stockholders hands. But this went really far from AI. Sorry for the rant, but I do worry for the future.
I believe blindly accepting something before even attempting to look into the pitfalls not a great idea. And we never see all the pitfalls coming.

Good enough is the keyword in a lot of things. That’s how fast fashion got this big.

The worry is deeper than just different changes in production. Not all progress is good, think of the broken branches of the evolution.
The fact that us don’t teach kids how to write already took a lot of different childhood development and later brain development and memory improvement out of the run.
Qith ai now drawing, writing and music became a single sentence prompt. So why keep all those things? Why literally waste time developing a skill that you can not sell? Sure for fun…
And you are bringing up efficiency. Efficiency is just a buzzword that big companies are using to replace human labor. How much more efficient is a bank where you have 4 machine and one human teller? Or a fast food restaurant where the upfront employee just delivers the food to the counter and you can only place order with a computer.
There is a point where our monkey brains can’t compete and won’t be able to exist without human to human stuff. But I don’t need to worry in 2 years we will be not able to differentiate between ai and humans. And we can just fake that connection for the rest of our efficient lifes.
I’m not against improving stuff, but qhere this is focused won’t help us in the long run…

I’m not sure at this point. The sewing machine was just automated stitching. It is more similar to Photos and landscape painters, only it is worse.
With the creative AI basically most of the visual art skills went to “I’m going to pay 100$ for AI to do this instead 20K and waiting 30 days for the project”. Soon doctors, therapists and teachers will look down the barrel. “Why pay for one therapy session for 150 or I can have an AI friend for 20 a month”.
In the past you were able to train yourself to use sewing machine or learn how to operate cameras and develop photos. Now I don’t even have any idea where it goes.