It also ignores how R&D and tech markets work. That "regressive tax on those who can't afford upfront capital" is an "R&D subsidy to early customers who are providing the upfront capital to lower the cost of solar". As solar companies get more wealthy customers, they can spend more on technology to improve efficiency, they gain economies of scale, and they can attract more financial capital on equity markets.

All of this has actually played out - the cost per watt of a solar installation is now 1/3 of what it was 10 years ago:

https://www.nrel.gov/news/program/2021/documenting-a-decade-...