As I understand it, even if the builder is wrong and they can't sell at 500k (there are only 200k buyers), affordability still suffers.
Why? Because the developer won't sell the first flat for 200k even if that turns out to be the highest achievable sale price, because it would mean immediately having to write down the market value of the other 199. (A paper loss of 200 * 300k, not just the one lot of 300k). That's going to mean the flats sit there unsold for a long time, while the developer holds out hope of finding high value buyers that don't materialise.
Net upshot, for a significant period the developer has reduced the available housing by twelve 200k flats (the replacement two hundred are effectively not available for sale at the going rate).
Why? Because the developer won't sell the first flat for 200k even if that turns out to be the highest achievable sale price, because it would mean immediately having to write down the market value of the other 199. (A paper loss of 200 * 300k, not just the one lot of 300k). That's going to mean the flats sit there unsold for a long time, while the developer holds out hope of finding high value buyers that don't materialise.
Net upshot, for a significant period the developer has reduced the available housing by twelve 200k flats (the replacement two hundred are effectively not available for sale at the going rate).