Better quality of living (in the long run even living longer) and less energy consumption on the AC may change that calculation.

You can buy them off the shelf and then put them up yourself. Of course then you have to calculate the amount of pain it'll be to put them up and the fact that it'll never be as good as getting it done by professional. Plus in my case they'll be a lot less blood involved.

10 grand does seem like a lot of money though. How large are your windows?

This is the real reason they disappeared - awnings cost money and don't increase square footage. That's also why every modern building is a boring box.

We didn't forget about them, it's still covered in architecture school. You can even make them look really cool. But they cost money, and that's a hard barrier to cross.