$1 in income is worth significantly more than $1 in tax deductions.
If someone was renting a property at $1000/month, it's still better to re-rent it at $800/month than to reduce your tax bill by something like $400/month (or whatever the taxes would be on the $1000 rent offset).
Something is broken in the real estate lending market because landlords do prefer lack of occupancy to lowered rents. I don’t know the industry well enough to know why but it’s definitely a pattern.
So the calculation is probably some combination of projected increase in occupancy, projected rent reductions of existing tenants, tax implications, and potential loan recalls.
My guess is most landlords are just trying to hold on till the end of the pandemic and hope that rents and valuations snap back quickly.
This is not true. At least in the US.