Being a landlord myself, I am surprised no one has mentioned the many insurance policies out there that can be bought to cover tenants missing payments (yes, not read it all)?
As with any investment there is risk, though I rent due to the fact I left the UK and there’s no sense in selling due to the poor equity, so landlords should mitigate this risk by taking the relevant precautions, landlord payment protection is one of the those, heck, you can even get the tenant to pay this if required.
Renting is no different from providing any other service, I provide accommodation with all the amenities and in the condition advertised, I expect my tenants to pay as per the agreed contract, its no different from you not paying for a builder or plumber for their work.
The insurance policy is there to make sure that if the tenant is not able then this can be resolved, just like I pay housing insurance to insure that my tenant can be housed if something was to happen to my house structural, it is my legal (and I would say moral) obligation since they are paying me for services.