Heavy industry will tend to migrate to sunnier areas.
A hypothetical estimate of 100% NYC’s electricity from Southern Arizona to NYC across HVDC adds up to ~1,300$/per person for infrastructure that lasts ~50 years.
East/west is even cheaper because people on both ends would want to move electricity. Florida solar kicks in early in the morning for California and California solar is still available late into the evening Florida time. You have some losses across HVDC, but you have losses and battery degradation with storage.
So, if by short distances you’re talking 1,000+km and 10GW then sure it’s billions. However, the US is only so big and Billion’s don’t actually mean much to move over 2% of the US’s total electricity.
Now my personal power output does tank during this period, but such extremes are local events. Further hydro, nuclear, and geothermal just don’t care about clouds.
AND not OR. To actually need 2 weeks of storage you would need both 0 output in solar for 2 weeks and 0 wind for two weeks and 0 output from hydro. That doesn’t happen.
You still get solar power on cloudy days, it just takes more panels to generate some specific level of power.
The goal is to minimize X$ for generation + Y$ for storage while guaranteeing sufficient supply. Any study approaching things from any other set of assumptions is going to give you nonsensical answers.