This is it right here. If the provision were made that councils could take the money from the sales and build more up to date housing for each generation then right to buy would have been an accidentally utopian policy that bank rolled housing safety for everyone forever - fuelling more Tory votes. Instead we got 13 years of Blair. Cheers Maggie!

Prior to the mid 1980s, housing in the UK was roughly split in 1/3s. One third in owner-occupier (you own the single home you live in) either outright or with a mortgage. One third lived in private rental (you pay rent to a landlord). The last third lived in council houses.

These were owned by the local government and rented to people on lower incomes at reduced rents and on very liberal terms. To all intents and purposes, you could live in a council house all your life.

Because this 3rd of residents tended to be on a lower income, tended to be working class and tended to vote Labour, Margaret Thatcher and the Tories saw them as a large threat to their electoral chances.

The tories also spent many years courting the upwardly mobile, middle class home owners because in an era of deindustrialisation, they were a growing demographic and largely voted Tory.

Right To Buy was, at least publicly, designed to give poorer people the right to purchase their council houses at reduced rates. This has two main consequences. Local governments were stripped of large amounts of their incomes, forcing them to strip services, starting a decades long decline in things like road maintenance, schools, youth services etc. A decline that has continued to get worse to this day.

The other consequence is most of those council houses which were sold were then flipped into private rentals. The market now is split with still roughly 1/3rd owner occupied, council houses (now mostly owned by what's called housing associations which have their own issues) are down to about 10% and private rentals now make up about 55%.

As others have commented, because the policy was designed to reduce the amount of people in council houses, there was no requirement for councils to use the revenue they generated from the sales into building new houses. This meant that money was largely used to plug temporary gaps in funding rather than ensuring the next generation of houses were built.

Some that held out like the big cities like Birmingham and some of the poorer London boroughs were actively punished by Thatcher with reductions in Central government funding.