Rents are high in SF because there is extremely high demand for those apartments at high prices, because they allow access to high incomes. The value of living in SF for a random serivce worker is not increased by them getting a $2k UBI cheque, it is decreased. For the tech workers driving the demand, $2k a month is not going to do much to change the value they assign to housing in SF either way. So I do not see how the UBI cheques would increase demand, and therefore rent, for housing in SF.
Companies can go ahead and pay more to keep them. You know what happens then? Prices go up more.
Where is all this capital flowing to? Landlords. Who didn’t pay for UBI, didn’t build the infrastructure, didn’t employ those people.