All this springs from two factors:
a) The decline in pension provision. Even the much-vaunted public sector pensions are shit compared to what they used to be. Unlike most European countries, the state pension is set at a low level, with low contributions. Finally, the private pension industry has managed to destroy confidence in it. This needs sorting out. I would go for European-style state pensions, with the recognition that this means higher NI and that it would apply to upcoming generations, not those who have not paid for it.
b) The deliberate privatisation of rental housing started by Thatcher's right-to-buy policy and her obsessive hatred of councils and council housing. (Municipal socialism.) This led to more and more people being forced into the private rental sector, which in turn led to a surge in demand, making rental properties a more attractive investment.
I don't blame landlords, although I agree a minority of them are exploitative and care nothing for tenant welfare. They are just exploiting an economic opportunity brought about by government policy, or lack of it. I blame politicians for fucking up pensions and failing to sort out housing. The latter being a consequence of leaving this vital provision largely to market forces.
In the UK we are too hung up on seeing houses as a profitable investment instead of as homes. No one delights when food shoots up 15% in a year, but when that happens to house prices people fucking celebrate.