Why is current not formed in solid conductors in the absence of an electric field?

(N/A) In solid conductors,the absence of electric current can be explained as follows:
$1$. When metallic solids are formed,valence electrons separate from their parent atoms and become free electrons,while positive ions remain fixed in a definite three-dimensional geometric arrangement.
$2$. In the absence of an external electric field,these positive ions oscillate about their mean positions due to thermal energy.
$3$. The free electrons move randomly in the space between these positive ions.
$4$. During their motion,electrons frequently collide with the positive ions,causing their directions of motion to change constantly.
$5$. Because the motion is random,at any given time,the net number of electrons crossing any given cross-section in one direction is equal to the number of electrons crossing in the opposite direction. Thus,the net flow of charge is zero,and no current is formed.