A lot of it has to do with permitting, building codes, and lack of competition. In Australia deregulation has led to pricing well below 1AU$/W installed. If we could adapt what worked there prices would come down like crazy.
In Australia an 18kW system.installed with two 10kW/h Tesla batteries should run under $30,000 AUD installed. That's somewhere in the vicinity of $23,000 USD.
I've been looking at upgrading my rooftop solar in Australia, since we have had 5kW on the roof for close to 15 years now. Ill put away the pennies for a few more years and pull the trigger at a similar time to when we get our first EV / PHEV with V2G.
Two of those is $27,200 minus installation and some solar panels to feed them (but the PW3 does have 3x 6.6kW solar MPPTs built-in unlike previous ones, so all you need to do is connect the panels directly to the PW3 and then the PW3 to your home).