Putting aside the fact that Vaal seems to maintain the ecosystem, and not soon after Kirk left, the natives are all wiped out.
You seem to be remembering a non-canonical and rather mediocre DC comic-book story from the '80s -- and misremembering it, since the natives were mostly alive and well in that story. Going just by the facts in the episode itself, we have no basis for making any such assumption.
1) How long has that culture been like that? For them that IS the natural course of things. Kirk has wiped away their way of life.
Slavery was the "natural way of life" on Earth for most of recorded history. It was mostly eradicated in less than a century. Earth survived. One of the biggest mistakes underlying many people's assumptions about the Prime Directive (particularly where TNG's writers were concerned) is that the "natural way of life" for any culture is meant to be fixed and unchanging. That's utter bull. Even an isolated culture undergoes some growth and change, and it's entirely natural for different cultures on the same planet to interact and transform each other; that's how progress happens.
It's a contradiction in terms to say that a state of affairs imposed by a computer god with a papier-mache snake face is "natural." Whether it was built by aliens or the Triangulans' own ancestors, it was still an artificial creation imposing an artificial social order. Talking about societies' "natural state" as if they were mindless animals following their instincts rather than societies of intelligent beings making choices about how to live is frankly rather condescending and dehumanizing. Every culture is shaped by its choices -- or sometimes by the choices of outsiders -- and will thus be subject to change over time. Except that the choice made by Vaal's builders deprived later generations of Triangulans of any choice. There was no chance that they could overthrow Vaal on their own and restore their ability to choose.
2) Dead serious here: That culture is dead. Dead. Dead. Dead. If Kirk just walks away 'leaving them to figure it out for themselves' They are arn't going to survive a year. And even if Kirk sends in teams like in 'Miri'...it would be like driving a tractor through a tribe of South American Indians who had never seen the outside world and making a mall. We're talking Future Shock to the nth degree.
Again you're being quite condescending and anthropologically misinformed. There are plenty of cultures in real life where one generation consisted of hunter-gatherers living as they had for thousands of years and the next was using laptops and satellite phones to coordinate their hunting and gathering. Cultures are more robust and adaptable than many Prime Directive apologists imagine. The problem is that the Prime Directive was supposed to be a check
against domination and condescension, a reminder that other cultures have the ability and the right to make choices for themselves, but it came to be interpreted in the TNG era in blatantly condescending terms -- "Oh, the poor primitives are too stupid and fragile to comprehend new ideas so we have to protect them from new knowledge even if it means letting their civilizations die completely." They completely lost sight of what the Directive was supposed to be about.
Respecting others' right to self-determination doesn't mean leaving them in the lurch when they're in trouble. It means being a good neighbor -- not forcing your ideas and decisions on them, trusting that they can handle themselves, yet still being there to help them if they're in over their heads, because they deserve the chance to get back on their feet. There is a difference between helping and interfering. It can be a blurry line and an easy one to cross, which is why the Directive is there as a check on our judgment. But once it becomes an absolutist, rigid dogma as it had in the TNG era, it does more harm than good, just like any dogma.
Once they get over the novelty of boning whenever they want, then what? Any introduction of ideas like 'self-determination' and 'creating your own world' is just further contamination.
More of that ugly condescension, that anthropologically incompetent notion that new ideas from outside are "contamination" rather than a normative part of how cultures evolve and grow. If you truly respect others' right to self-determination, then you trust them to be able to make their own decisions about how to cope with new knowledge.
There only appear to be like 30 of them.
Oh, come on, that's because the episode didn't have the budget to show more. It doesn't make any sense to assume that was literally representative of the entire population of the planet.
