It is true that some don't have jobs both most are either a) not interested in working in a big law firm and so will be applying to government, non-profit, and small law firm jobs this spring, or b) not interested in being lawyers.
And as with any other journal, the membership doesn't automatically get you anything -- you still have to interview well, not be an a-hole, and have good grades -- and LR doesn't necessarily mean you've got any of those things locked.