Having a tenant is some risk -- they might mess the place up and cost you some money. If you've got profitable housing above then a new tenant might make noise

Having a tenant is some risk -- they might mess the place up and cost you some money. If you've got profitable housing above then a new tenant might make noise or smells that upset the neighbors. If it's empty you can wait for a really excellent tenant to come along. Of course, that's only sane if the cost of leaving it empty is very low. Which is indeed the case. I lived next to some church property that was similarly blighted: the church paid little or no taxes and wasn't fined for having the property in disrepair. The congregation had all fled to the suburbs. So what was the incentive to put in work finding someone to rehabilitate and then buy or rent the property?