Proof? If you stand outside a solar panel manufacturer in china with your arms out, they will sell you a working 250 watt module for less than $0.80/watt. By the time you get it to the US, you've added $0.40 for shipping/middlemen. Pricing here. We'll round to get to $1.25 a watt for a solar panel. If you do all the work yourself, you'll spend another $1.50/watt buying the hardware needed to mount, install and wire the panels. You'll have to spend another $1 a watt for the permits and a specially certified electrician to do 1 hr of work to connect the last foot of cable. (Rip off alert!) So 40% of the cost of this solar system is caused by regulation that doesn't add much value.
And that's if you do the work yourself so think how much time you've expended in 120-180 days trying to get those permits. Paying someone else to do all the work will take this $3.75/watt installation up to $5.50 to over $7.00 a watt. Getting reasonable permitting and more competition in installation/electricians is what we need to drive the costs down. That means we need the VOLUME of installations to climb to Germany-levels so that we stop letting contractors and towns rip us off and keep us from installing these systems on our homes.
Some calculations to show the impact. A 4 person family home generally would need a 10kw system to cover their whole energy bill (double production when the sun's shining, grid connected at night). We're talking $35k for a DIY system, which could as much as $10k lower if the permitting/contractor racket didn't exist. We're talking $50k-$70k if you let a contractor do the work and laugh all the way to the bank. Most folks only put in a 25-50% system because it's too much capital to expend. $35k for a system at today's mortgage rates put it within 10% of the cost of that grid electricity... with no government subsidies and assuming no increase in grid electricity rates... Add those subsidies and you've got a 3 year NPV.
Full disclosure: I work in the solar power industry building machines that are used at solar panel manufacturers to make cells to be placed into modules.