https://www.generationrent.org/sadiq_khan_publishes_vision_f...
There is a massive amount of people in that generation who are wealthy simply because of that policy combined with large rise in house prices. This selection of people + regular homeowners no matter the party line, will always vote against any policy that a) has the possibility to curb increasing house prices or b) fairly taxing those profits.
We don't have anything like property taxes in the UK, and the closest thing we do have is council tax which (laughably) is the tenants responsibility. It's a situation that no party has a realistic chance of being able to solve. Even if there were MPs brave enough, it's a difficult problem to navigate because there's millions of people with 0 savings (retirement or otherwise) but now own 500,000gbp+ houses.
If you tax that appreciation in value or your policies reduce these prices to sustainable levels then you suddenly have to now provide social security for millions of people who now will need a lot of extra assistance via state pension.
They've already tried but this is a Tory government so they cannot completely destroy the private rented sector.
But be sure that if Corbyn/Labour get in power soon this will be implemented no matter the economics against it.
Not that this contradicts anything you’ve just said.
Edit: Sources https://www.bloomberg.com/opinion/articles/2018-01-18/yup-re... https://realestateinvestingtoday.com/how-rent-control-reduce... https://www.rpbg.org/index.php/rent-control-it-doesn-t-work https://www.multifamilynw.org/news/the-high-cost-of-rent-con...