Did people seem to find shit getting on everything deep? Did serious writings explore the experiences of all manner of shit, and the nuances of the feces and piss involved?

It doesn’t seem like it? Maybe read Gargantua and Pantagruel for ideas…

Some types of suffering, like chronic pain exacerbated by a shitty repetitive .annual labor job, have never gotten much attention. I think that's like the mundane happiness you describe.

Literature lingers on complex emotional suffering, I think, because it's actually more interesting by virtue of being complex but understandable with effort.

It is like a mind tied in complex knots, partly connected to the structure of the world.

I think there are complex joys as well, and literature can have as much fun with those.

I think we focus on suffering because it benefits from our negativity bias, and it seems more virtuous to spend our time understanding suffering than joy.

I think a careful unwrapping of the complexity of a joyful experience, like attending a party and interacting with people in ways they individually appreciate, or the beauty and strangeness of the walk in your other post, ultimately hold just as much interest and virtue, once we don't need to deal with so much shit.

The above just goes to show just how abnormal true 100% contentedness is seen by this society, esp. for someone to even think that such a state would be "boring and empty", or that the individual(s) in question are somehow repressing their pain and/or dualities.

I disagree with your take.

Suffering is quite unlike shit in that once we get rid of shit, the shit you got rid of does not come back, crawling up the toilet. Suffering is not some "thing" you can get rid of, but rather a quirk of our neurophysiology. Get rid of the most immediate cause of suffering, and your brain adjusts its thresholds to seek the next worst thing; this is called upregulation.

Two related real-life examples: if you are walking in an uncomfortable shoe, you are aware of the uncomfortable shoe. Step on a bad thorn that pierces your shoe and foot, and now your attention is wholly on the thorn. Take the thorn out, and once your wound has healed, your attention is back on that shoe. Inversely, imagine getting a cast on your foot and ankle because you broke it. It may be uncomfortable at first, but as you heal it becomes alright. After a month or two, the cast is removed. When you step on the floor, it is intensely painful! You would not be alone; many patients feel this pain after removing a cast, because their foot has become sensitive from not walking. The same applies to people who wear shoes all the time trying to walk barefoot on gravel; it really hurts them, but those who walk barefoot all the time can do it without issue.

Have you considered that maybe all the writing and philosophising about suffering might be for a reason, and that generations worth of our brightest minds have considered this issue and thought "damn, this suffering thing is inescapable, even if its previous causes vanish!" and then asked "but why is this the case?".

In fact, I think you may have hinted at it in your comment about people living many happy years as boring and empty. What are those but types of suffering? And why? What makes it so? Furthermore, have you not joined the ranks of these very same people, philosophising about suffering?

Respectfully, I think you've fallen into the mistake of dismissing the Sazen (https://www.lesswrong.com/posts/k9dsbn8LZ6tTesDS3/sazen) of many prior thinkers, perhaps because you did not exercise the skill of "listening to wisdom" (https://www.lesswrong.com/posts/5yFj7C6NNc8GPdfNo/subskills-of-listening-to-wisdom).

Maybe if you find the truth in the core of the "suffering is inevitable" approach, you might realise that seeking discomfort, in wise and non-permanently-harmful ways, is actually a way of reducing the suffering you experience from things that once used to harm you. Of course this is within the limits of your body, but the barefoot walking example of earlier is a decent one, and is up there with working out and fasting, amongst many others.

My prediction is that if humanity survives, it will cling onto suffering in each context only until its meaning and profundity is sufficiently recreated by other means.

Intense pain will go first, then annoying and inconvenient pain, then distracting pain, and gradually people will adjust to higher valence landscapes until the whole spectrum is above our current default line.

In fact, it might not be that difficult a transition. Even today many people spend hours a day browsing social media, watching YouTube videos, playing video games, or meditating, all in the pursuit of higher valence. Legal prohibitions might turn out to be the main force slowing down the eradication of suffering from daily life.

I say often that the fundamental unit of human experience is the story. We love stories. And the best stories are the ones with a sprinkle of drama in them. A story about a rich kid who never struggled? Boring! A story of riches-to-rags-to-riches? Sign me up!

Why? Because stories are a form of Supernormal Stimuli. We like to live vicariously through the lives of more interesting people. And it just so happens that the lives of interesting people are usually filled with some amount of suffering that they're able to transcend. That's why people like superhero movies. We relate to the struggle and rejoice when the hero wins the battle (for maybe we, too, can overcome our struggles).

There will be plenty of new sufferings that we haven't imagined yet. And if we are wildly successful at avoiding all kinds of suffering, we'll all be bored.

Every new human advancement solves a problem but creates new baseline expectations, which are new opportunities for disappointment.