The authors cite several earlier local studies that demonstrate the phenomenon. Researchers in Baltimore, Cleveland and Dallas “found that some landlords viewed the additional revenue from late fees, enforced by the threat of an eviction filing, as a supplemental source of funding in addition to the regular rent roll.

I know there are predatory landlords out there, but in my personal experience most are just regular people trying to earn an honest living and support their families. If you're a good tenant, most will work with you if you're late on your rent a couple times. I seriously doubt that many are hoping for their tenants to be late so they can rack up extra late fees or whatever. I really don't understand this trend of demonizing landlords who are providing a vital service and are mostly decent people.