Because we cannot know how everything we use is assembled, we must have faith that its structure is sound. Delegating certain responsibilities to our children's education means that we've lost touch with a part their development. Handing over our basic right for self-defense means that at a very personal level we've left ourselves vulnerable to assault. Yet, experience has taught us that mistakes are made - no matter how educated and skilled the professionals we leave in charge are. Oversights produce flaws.
Planes fall out of the sky.
Sometimes our children turn out bad. Criminals have taken over the night - despite the full attention of our civil authorities. Though we can never be sure that when we entrust others with matters important to us that everything will be done perfectly, we continue to do so because the benefits seem to far outweigh the prospect of trying to do it all ourselves. Presently, there are reasons to believe that we cannot entrust the health of our planet to the experts. The rate of species and biodiversity loss is on par with some of the great extinctions of the past.