There is plenty of evidence countering a faith in growth. A culture that has existed for several orders of magnitude longer than ours is strong evidence. It would even if they were as ignorant and fearful as you describe them. That there were the opposite strengthens the case.
I'm not sure if you were suggesting that people in our culture are not ignorant or fearful, but I see a lot of it, or if you're suggesting that past flourishing means it will continue, but I wouldn't bet on it unless we change a lot.
The culture you are referring to did so for 100.000 years because it couldn't consume enough of its surroundings for it to have to worry about anything.
We don't live in such a world and unless you can give me an alternative to growth that allows all the people who haven't gotten up to our standards of living then I am not sure what you are trying to get at.
Of course, our culture is also ignorant compared to the future that's not the point. The difference is that our culture is learning and evolving, their culture wasn't until they got out of their environment and started exploring the rest of the world.
I am not talking about past flourishing I am saying that the only way (I would welcome arguments for the opposites, the bushmen isn't one) for humans to keep flourishing is growing.
The fact is that we have gotten increasingly better and better at converting the earth's resources into serving our needs and have been able to effectively optimize and improve our ability to get more out of less. Most importantly wherever you see humans flourish and get wealthy enough the environment improve because we start to care about it and get the power to do something about it.
Humans didn't use to live in harmony with nature, they used to live in fear of nature. Mother nature is brutal to humans and it's only because we have gotten better and better at controlling it that humans could flourish.
I am unconvinced that minimizing our impact on nature is the moral thing to do and unconvinced that what we are doing right now is by any metrics worse than what those bushmen did. Too many people romanticize humans relationship with nature.