Petition building of bungalows for an aging population

With the facts of an increasing older aged population very much in evidence since the last census, why is it that the present guide lines for building housing are weighted toward 3 to 4 bedroom houses?
It has come to my attention that builders are being refused permission to build bungalows into their site plans on new developments.
Surely the government should be encouraging builders to build at least equal numbers of reasonably priced bungalows in their developments since this would do two thing,
1, give older people who are looking to downsize somewhere to aspire to.
2, open up the houses that these older people are leaving thereby making Family homes available for younger people who presently have much less choice