Are you joking? In the UK they can offset rental income against their mortgage payments (EDIT: mortgage interest payments), meaning they only pay income tax on their "profit" while also benefitting from the capital appreciation. (Admittedly this is changing from 2017 [0])
This, coupled with low interest rates means that landlords will take out additional mortgages to buy new properties even if they could afford to pay cash.
Landlords have been able to act like mini hedge funds, making huge bets on the housing market using cheap borrowed money. Some will get badly burned when/if interest rates rise and property values fall, but that doesn't look like happening any time soon.
This, coupled with low interest rates means that landlords will take out additional mortgages to buy new properties even if they could afford to pay cash.
Landlords have been able to act like mini hedge funds, making huge bets on the housing market using cheap borrowed money. Some will get badly burned when/if interest rates rise and property values fall, but that doesn't look like happening any time soon.
[0] http://www.wrigleys.co.uk/news/property/budget-2015---tax-ch...