How does infrastracture make me money?

I have been wondering this the whole team, how does it make me money or can someone explain it to me?

it doesn't. only passively through the welfare index

And when you have a good welfare index, CEOs can see attractive your country to build there.
Private inversion in your country its good.
Cheers!

Thanks :D

Your education, health, and transportation affect your productivity in the corps, along with their upgrades.