If you take an honest look at the curve of your graph, it supports my position.
Look at computer costs, The cost comes down exponentially at first, and then levels out. A computer today, costs about the same (or more) as a computer costed ten years ago, and they are just not that much better.
We often hear claims about how solar and wind are cheaper than fossil fuel, but with both solar and wind, you still have to have duplicate capacity in fossil-fuel or nuclear generators. I don't doubt we'll continue to see improvements in solar, but nuclear is clearly a much safer bet if CO2 truly is an existential threat. And again, solar does not work at night, and often does not work during the day.
Unless perovskites PVs will work perpendicular to the sun, how spraying it on windows even work, much less reduce costs? Solar panels already cheaper than a good window.