"Property management" is what a landlord does in a functioning housing market (I.e. one where the price of housing is holding steady, so a landlord can't make money just renting while the land value goes up on its own). It's what makes renting preferable to owning in a functional market - you pay extra for convenience and flexibility.

What you're saying is that most landlords don't do their job. Which is correct, and also why everyone hates them.