SF is on a peninsula and Manhattan's an island. Chicago is relatively low-rise as well, but there's a lot more land in back of it. I hate the SF planning process, but there's no question that the city's growth is partly constrained by geography.
I am thinking of moving to the Chi and was surprised that rent is less than half of the average bay area price. A lot of craigslist ads even tell applicants that they require a check for eviction court as part of their deposit. In total contrast to SF's rent controls.
(2) Definitely move here. Chicago is a fantastic city and the reason you don't hear about it more is that it's underrated.
If there's a kind of neighborhood you're interested in living in, I'm happy to help point you in the right direction. You should have no trouble finding a place.
But the issue here is there is nothing good in soma besides jobs. In the weekend, I don't want to go to soma. I want to go to Northbeach or the mission or the castro.
All that being said, I haven't lived in Dogpatch, so it could be fantastic.