I suspect I have the unpopular opinion, but I don't see this as an especially big deal. Yes, I understand this is an especially sensitive issue for SFers. And yes, it sucks for the guy. Renting has its perks, but this is part of the risk of renting; you're living on someone else's property. Repeating that--it's THEIRS, not yours. If you have no current contract (lease), why should they be required to rent something to you under terms you like? Where else does this occur? When some business raises rates, it is the exception, not the rule, that you're "grandfathered" in to a previous rate.
I get that having to move and find a new place to live is a bigger deal than if McDonald's raises the price of a cheeseburger by a dime, and that's why there are some protections in place (requirements of notice, an eviction process, etc.), but there is no indications that those aren't in play here.