I've got 28 juicers. I call them "my teeth".
I get the point, and it's a good one. Humans have come this far without mechanical juicers, relying only on our teeth to grind food enough to extract the nutrients. However, a large part of our modern diets include highly processed foods and refined sugars. In some cases so highly processed that it barely qualifies as 'food'. Most of this stuff adds nothing in the way of nutrition and may even leach nutrients from the body! (why do people think they need vitamin 'supplements'?) I'm thinking that 'juicing' may be an effective way to get a lot of the natural vitamins, minerals, enzymes, amino acids, antioxidants (all the stuff that goes away with overprocessing) the body needs to stay healthy.
I don't know anybody who eats the recommended 3-4 servings of fruits and vegetables every day, do you? If they can be packed into a juice drink, even once a day, it would seem to be better than none at all. As far as the bulk, the fiber, sure it's necessary, but again, I don't know anybody who gets it mainly from fruits and vegetables.