Sorry, you're reading it wrong. It isn't about old people, it's about entrenched interests, from young, old, rich and poor people who constantly pass legislation stopping others from converting their (others') houses into apartment buildings.

Entrenched interests != longstanding residents. There is some overlap though.

Think of it like the people from Los Altos Hill passing laws effectively banning poor people: the minimum lot size is 1 acre, and all lost can only have on family living in them.