I feel for the renter, but shouldn't the landlord be able to do whatever they want with their property?

Rent is going way up because there aren't enough homes in sf for the amount of people who want to live there. The city is to blame for this problem. Why is sf such a flat city? There should be a lot more tall condo buildings but as I've read it seems the city blocks any structure over 4 stories.

Raising rent will cause lots of low income people in sf to have to move. That's not a good thing--but what is the answer here? How do other large cities deal with this problem?