That may work for larger buildings. (As an aside I wish they would make it mandatory to for apartment/condo buildings more than four or six stories to use geothermal for the heating and cooling.) I don't think it would work for smaller buildings and homes.
I just replaced my furnace and A/C in addition to looking at getting solar panels put in. Now this is for eastern Ontario so the economics will be different for a lot of places in the US. The numbers I'm using are retail but their relative values should be similar to a trades person.
I'm in the suburbs so that means for a geothermal system I would need to drill vertical holes for the system. I didn't get one priced but they range between $30k and $40k with $10k for the drilling.
There seems to be only two air source heat pumps on the market for my region and they cost around $13k. Plus they would need a backup heating system for the extremely cold days. So with installation estimate $20k
A 98% efficiency natural gas furnace with a 16 SEER A/C comes in around $8k.
From looking around at solar power it costs about $8k to install the basics (wiring, inverter, etc) and then it's approximately $2200 per kW of panels.
In all the systems there is a fan for circulating the air and you are going to have the installation costs for the solar power. So it basically comes down to adding solar panels to cover the difference between the A/C and the heat pumps. The builder could also decide to go up to a SEER 21 A/C if it was cheaper than adding the solar panels or increasing insulation.