It's all about the New Homes Bonus.
https://www.gov.uk/government/publications/new-homes-bonus-final-allocations-2020-to-2021
In essence, in spite of the fact that more Dovorians are dropping dead than being born each year. To balance the books (and every election they crow about the fact that we have the lowest Council Tax around) DDC need to keep on encouraging new builds to maximise their income.
It's a bit like drugs. At first you only need a few extra houses. Nd no great harm is done and you convince yourself your habit is under control.
Unfortunately when their bonus vanishes you need to build even more homes to cross subsidise services for the increased population (usually fleeing our vibrant and multi-ethnic capitol!) who have filled up the extra houses all needing schools, roads, doctors etc.