Yep, I agree that the costs of running a professional business are
very high.
That factor along with the fact that the field has an ample percentage
of conmen and hacks has given rise to the DIY option.

New online HVAC sites are popping up left and right. Some even
promote a co-op arrangement where the homeowner does the rough in and
they find you a tech. for final connections/checkout. (just like
buying your tires at Tire Rack and taking them to the shop for
installation and in the process save a bundle).

R410A is making this easier by not requiring EPA licenses. (yes
venting is still illegal but most systems come precharged). New
refrigerant developments with no ODP and no greenhouse gas effect
could really accelerate this shift.

When you can buy and install the components for $2500 that a
contractor normally charges over $10,000 for then the economics will
shift an increasing portion of HVAC to DIY. (Throw in $1000 for misc.
tools and supplies and it's still a huge savings).

The next phase will be when a manufacturer steps up and offers simple
lineset connections and strikes a deal with Home Depot and Lowes. (ie
precharged/no brazing needed)