Isn't it generally a temporary lifestyle to teach lessons about self-reliance and adaptiveness and not some permanent lifestyle like say, the Amish, who do use modern healthcare despite living a 19th century lifestyle?
The amish don't make any particular effort or have any particular desire to live a 19th century lifestyle. They simply avoid technology that they consider to have more downsides than upsides.
The Amish are more opposed to greed than technology. The two often go hand in hand but not always - individual congregations decide for themselves.