Whilst it is true that previous attempts at rent control have led to adverse consequences it is equally true that a continuous upward spiral of rents when incomes are not rising is not a sustainable postion.
Sustainable development must include social and financial dimensions ensuirng that the development meets actual needs and and is accessible to people to meet their needs.
A rent cap may be a crude tool but without regulation it is possible to foresee a boom and bust situation, where supply rapidly expands on the back of rent inflation but a change in the wider economy, increasing confidence and or mortgage avalaibility makes buying more accessible. The rental market then collapses, small investors lose money and house prices fall first making homes more affordable but then reducing confidence.
Managing the market is a valid way to avoid a collapse.