Do you realise how supply and demand works ?
If many landlord sell up, supply drop and rents go through the roof. Many what you call “ ordinary people “ who are now renting do not wish to / are not in a position to buy.
Im always amazed how many people don’t understand the position of the majority of tenants in the Uk. They are not all middle class couples trying to get into the housing ladder in the south east.
They are single mums on benefits, retired or disabled single people and couples, foreign nationals in the uk for work for a few years, people moving to another part of the Uk for work, couples moving in together for the first time, students ( uk and international ), women leaving unhappy or abusive marriages with their children, , young families with only one wage coming in, households dependent on benefits, refugees and asylum seekers, people getting out of homeless.
Your clever plan to make rented housing even more scarce and expensive will penalise all of them.
Soclai landlords are unable to house all of them. It would take years and billions of pounds . And no doubt you would object to your taxes increasing massively to pay for it
.