frank1492 wrote:
I think it is obvious that a particular skill can be learned
by reading the right material and doing the correct research.

Theory can be learned by reading; actual implementation isn't
necessarily quite so simple. There's also "art" involved beyond the
technical aspects.

While not impossible, unless one already has the skills in hand,
learning the necessary skill set practicing on a new system install
isn't conducive to a quality installation.

Learning sheetrocking or how to sweat copper plumbing is pretty simple
and easy enough to fix screwups with very little cost or impact other
than time. Messing up a new HVAC system install is much more costly and
difficult to repair the damage.

....