Even in today's society, people who pay rent have squatter's rights. It can make it really hard to evict someone who doesn't pay. For example, see this article: https://www.landlordology.com/how-to-get-rid-of-squatters/
The landlord can't do anything to the tenant to make his property inaccessible until the court kicks the tenant off the land or out of the apartment. It can take years to get rid of a tenant who won't pay.
Depends what state you are in.
In my state, you get a hearing date and 30 days later the sheriff forcibly evicts you.