Technological progress is the secret to price reduction. No government interaction required or even wanted, it's usually much more likely to create problems...
That's generally true, but there are exceptions. Solar panels are very cheap now because of decades of government subsidies. Battery electric vehicles are still more expensive than their regular counterparts, but certainly one day they'll be cheaper (they have many more fewer moving parts). But would they have caught on without government subsidies?
Same amazing price reductions with li-ion batteries which are used in every mobile device. EVs? Who knows - but since the government is subsidizing gas prices, that market is already corrupted beyond salvation.
Governmental subsidies managed to skew demand and create market aberrations like the rainy Germany covered in solar panels while their nuclear sector was being closed.
I've seen smart glass demoed at a home show 25 years ago. I thought it was way cool, until they quoted the price. It's no surprise it hasn't gotten any traction since. Oh, it also consumed electric power when in dark mode, as much as a light bulb. It's not a passive system.
Window blinds, louvers, eyebrows, shades, etc., all work fine and are cheap.
BTW, when I lived in Phoenix in the 1970s, people would tape aluminum foil or newspapers on the windows to cut the heat intake. The newspapers would block most of the solar heat, but would let the light through.
Here in Seattle I made some reflective panels I can just stick on the windows when we have a heat wave. Plenty of light still gets in.