There is the other side of the coin here, in that if landlords are trying to expand their businesses / finance improvements to properties, they will be looking at taking on more debt. This will increase their average rate, and they will absolutely pass that on to their tenants. The question is of timeframe over which this process will occur.
In the US, improvements/repairs to rental properties are extremely tax advantaged. You might take on debt for the initial liquidity, but as I understand it's easy for landlords to use these expenses to effectively nuke their income tax liability.
