The term rent selling stats with 'rent' for a reason. The maintenance on any single property is miniscule compared with the rent extracted. Added over many properties, sure, might be a lot of work. But you're also getting a lot of rent.
The bigger part of the problem is the tendency to pass on the tax on passive income to the tenant.
This is also why when someone has enough capital to buy enough properties to extract a full-time wage out of the rent, you can be sure they're also not going to be doing the work themselves.
They'll offload it to a property manager/real estate agent to do all that work.
The bigger part of the problem is the tendency to pass on the tax on passive income to the tenant.