We understand the rent is still due and payable, but even if the tenant does not pay, it will be up to the landlord to go through l/t court or other collections post-moratorium to sue for the money. 

Then he could give every home away for free, just collect lot rent and still have a net income of around $300,000 with a fraction of the work and risk.The whole goal of an income property is to maximize the income.

I am not even going to go into mangement problems, tenant drama, domestic and violet crimes, vacancies and rent collection issues..I have seen the backend of the story as well, because I am getting calls from out of state investors, who have accumulated small portfolios of these low end properties and when they start they are loosing money after a few years they want to liquidate the portfolio which is not that easy. 

Contact a debt collection company and have them handle it for you. 

If this correct, why people buying 100 units with multi millions and only collecting 4 or 5% cap?

To the OP  I high suggest you get on Net flix and watch the American Greed Episode on Remington Financial and or Google Ingrid Robinson  Remington financial and read in depth how these pump and dump fake lenders set them selves up to just collect up front fees and never make loans.. 

My offer was rejected so the owner is now collecting less rent, but still has the same expenses.

If they are paying, just keep collecting.

Harder to finance.Less appreciation.Tenants that talk to easy other.Higher maintenance.Higher turnover.And you have 4 rents to collect, and most likely one will be late.Yes, you can get a bit better rent per price than you can with SFH, IF you can collect it.And not sure what a C neighborhood is, but not good enough.BTDT, gave my last one away..... years ago.

*** What do I need to do from a licensing standpoint to collect leasing commissions for vacancies my team leases up?