I think what Willem meant by 'survivance" in that context was the fight for the survival of a "wild" way of life as a culture, not the traditional meaning of the "survival instinct" as something that kicks in when someone is faced with death. But I'm sure that for many people, the attraction to rewilding has something to do with that type of "survival instinct."
Initially, I think I was led to rewilding through experiences that made me rebel against the dominant culture. I think most young children still have some bit of "wildness" in them that stays around long enough so that they remember it when they grow older.
Through our experiences, I think some of us are able to hold on to our wildness longer than others. I was a middle child (of divorce), a boy scout (and my dad took us camping often), and an overall introverted and sensitive kid.... I think this made me able to "stop" and keep a different perspective than the majority had, although I sometimes suspect (like you do, John and Thuder thighs) that rewilding has always been "embedded in my psyche," and that it just needed some support to come into consciousness.
But as I get older, and more societal civ pressures try to mold me to their desired shape.... that's when I think the survival instinct kicks in. I seem to have a need to hold on to feelings that I know are true to nature, and now if I try to "do civ's bidding" it just feels physically and morally wrong.
So, to answer your question, I think it was a little of both rebelling and surviving for me.... Rebelling first...then keeping the spirit alive. But I'm honestly beginning to think the rewilding spirit originates from somewhere deeper and that it's realization is experiential, and more likely in some people than others.