And the hard, hard lesson of the First World War was that lack of a standing army made timely mobilization impossible when large bodies of troops were required. We were lucky, in that war, that we had 9+ months to assemble our troops (who were dismally short of armaments, it must be remembered).
The idea of not having a standing army is fine, so long as one is never seriously threatened by another nation which does have a standing army. To fail to establish a standing army in such cases is to commit suicide.
Just an observation: if every capable citizen, male and female, is armed, then there's no "mobilization" required. It's true that it would be impossible to go around invading other countries without assembling an army, though...