There are a lot of issues in academia, but that number (40%) is not one of them. Not everyone is suited for an academic job, and doing the PhD is not enough to understand what it is to do independent research/find your niche what you are good at/enjoy. I think in many universities now there are career development programs that help people transition to industry. Also now it is more openly discussed that many people will not get an permanent position, so postdocs are more prepared and that is healthy.