If every SH tenant knows that as soon as they do a bit better they have to move into market housing (shit and wildly insecure) we incentivise people having no social mobility. Basically encouraging people not to improve their lives.
@MrsTerryPratchett I'm appreciating & learning a lot from your posts. But I don't think I'm suggesting that the OP should contemplate moving into the private rental market. An inheritance of £250 k is a substantial amount to purchase a home, thus offering @howdoesitworkthen far more security in her housing than any kind of renting.
And yes, social housing tenants pay rent, but it is not a current market rent generally.
I agree that current market rents can be pretty usurous (I have a rental property myself and reduced the rent by 20% while my tenant was furloughed in 2020, and haven't increased it since. They're good tenants & happy in the house).
BUT - it's the perception of an unfair disparity in rental opportunities. Those secure in social housing still pay rent (and taxes) but - I would assume from what you say - they are not paying current market rates. This is a good thing, but must be very very hard to see for those people unable to secure social housing, although they are eligible for it, who are forced to pay market rents, and suffer all the precarity of housing involved.
There needs to be a solution which balances individual need and social need. Allowing a social housing tenant to remain in scarce social housing when they have the capital means of housing themselves securely, is not that fair or transparent balance.