One minor caveat here is that the big push for solar cells has been isolated power requirements ~ e.g. safety lights, highway signs, rural emergency phones, etc. There's really only so much demand for that stuff and once it's up that's the end of the market.
A flashing McDonald's sign on top of Mt. Everest is a possible candidate for solar cells but it's not likely, nor are many other "feel good" ideas like that.
Another serious impact into the solar cell business has come from dramatically improved fuel cells, AND, surprise of surprises, dramatic reductions in the power requirements needed to operate TV, radio, computers, etc.
While doing some "cleaning" the other day I came across a really handy-dandy device I always carried in my brief case. It was a ruler with metric and American standard measurements ~ about a foot long. It has a touchpad keyboard with all the numbers and signs, a small LCD bar and a small solar cell bar.
There are formulas for converting all sorts of things into all sorts of other things.
I paid $1.00 for it a long time ago.
Solar hasn't really taken off!
I’ve got all kinds of solar charged gadgets here at home but Michigan isn’t exactly the prime candidate for solar.
Solar is great for space and deserts.