Hello Marc,
Sorry I haven't replied to your post before now. Somehow I didn't get the notification. I wish I could give a positive and practical answer to the question of how we alert people to the importance of soil - and many other aspects of human ecology - before it's too late. I've been wrestling with this one for 35 years and the solution just seems to fade away into the distance. We're very aware that you need to start changing before you're forced to and equally aware that the great majority of people won't change till they're forced to.
As I see it what we have to do is to focus on creating a viable alternative. This doesn't only mean the technical side of permaculture but also the human side. Here I think it's hard to overestimate the importance of working at the community level. Governments are always too little too late, as individuals it's all too daunting, but bang in the middle of the two is the community level and I there I believe the hope lies.
In fact there are some signs of hope. For example in this report to the United Nations, which states that agroecology (ie permaculture), not industrial agriculture, is the only viable way the world is going to feed itself in the future.
http://www.srfood.org/index.php/en/component/content/article/1174-report-agroecology-and-the-right-to-food
Ideas and accepted wisdom can change faster than we sometimes think.