As mentioned in previous posts, structural millimeter alignment is not the goal of all DCs. A vertebral unit can be fixed in perfect alignment in the neutral position and be highly dysfunctional if it remains so during flexion, extension, or rotation. Thus, maintenance care to mobilize fixations in an early stage would be preventive in asymptomatic patients. I would never compare my health service to that of an automobile mechanic. The human body is much more than the sum of its parts.
Adjustments are to be done only in the presence of a sublux that has already occurred.
An adjustment without a sublux is a mal-adjustment and would be malpractice if the profession upgraded their understanding of same. You don't front end align your car when it is not out of alignment. Of course adjusting a subluxation correctly does prevent, or abort, the continuum and perpetuity of neuro aberrance and the trickle down systems malfunctions, arterial vaso constriction, somato afferent excess traffic, accelerated tissue degeneration of viscera, and impaired longevity. But you give us no valid arguments to back up your conclusion. It's funny how patients figure out maintenance care on their own.