That's the benefit of a division of labor.
I didn’t say the Sioux started manufacturing plants. I am saying they radically changed their life style, as many peoples do when they encounter superior technology.
Yes and after obtaining horses, the Sioux first waged holy jihad against tribes of the Plain well before coming in direct contact with Europeans. In other locations such as Florida, the same Indian tribes were in contact with Spaniards for centuries yet never managed to upgrade in any meaningful way.
In any case, stone age technology was not necessarily primitive. An indian living in South Carolina, a west African, and a French peasant who were contemporaries in the 16th Century lived on pretty much the same comfort level, even with the superior technology available to the last. Which is why, by the way, that a French peasant could immigrate to Canada and endure the hardships of a savage New Land, whereas you or I probably would not survive for more than a few months under those conditions
Darwin was definitely ever present. I'd be interesting in knowing just how many European newcomers didn't make it.
As for the life span of an immigrant, that depended. It took the Europeans about three generations to acclimate. Very often an indentured servant did not live out his seven year term. Bad water, bad food, and hard living will do that. And that's only on the trip over. Plus many of them were not in great health when they started.
Which brings me to what we owe to modern medicine. As late as 50 years ago, we were ravaged by diseases such as Polio. Many a worker was carried off by the lack of a tetanus shot. Giving them the right shots enables us to send troops into pestholes and expect to come out alive.