Security.
The answer is security.
In an ‘ideal’ world people would start in low cost housing and work their way up towards buying a property, saving as they rent. Then go on to buy with a fluffy cloud to put their head on and a unicorn in the back garden. We don’t live in a ideal world. We live in a world where life can throw you a curveball at any time and if you’ve actually been skint and struggled to feed yourself etc, there’s no way you are going to give up a secure tenancy with rent you can afford, in favour of a private landlord just because things are relatively comfortable for you at that particular time and someone else may need your home. Which also is another factor, just because it’s local authority on paper, does not mean it’s not someone’s home in real life. Most people rather die than lose a home, even if others might just see it as bricks and a roof.
Is it fair? Probably not, although we all have dues to pay and the wait for social housing, that everyone goes through, is an endurance in itself. The answer is not people giving up their tenancy for others, it’s that the government need to make good on the manifesto pledge that they would build 20k starter homes. Only they can’t right now due to the fact that they are tit and the country is slam dunking into an inevitable recession.