Let's look at your example of a roofer, assuming he owns the company.He has to pay for employees- they still get paid, even if they are not giving 100% effort.He has to pay his workers to go back for warranty work - effectively paying them to do the same job twice.He has to pay for equipment, even when it's not being used 100% of the time.- but the company he bought it from still gets paid.He has to pay for advertising, whether it works or not.- but the advertising company still gets paid.He has to pay for accounting services, payroll services, tax services, legal services, etc.- they all get paid whether he makes money or not.So, what's your point?

Realize that you need to design around it.  

Detroit requires strong local relationships to navigate things like neighborhood nuances and property management effectively.

Alternatively, in addition to the per diem in § 17 (Possession) for failure of Seller to timely deliver possession of the Property after Closing occurs, Buyer may elect to treat this Contract as being in full force and effect and Buyer has the right to specific performance or damages, or both.22.

You also will still need to manage your property manager  - ie, stay on top of expenses, ensuring your property is being managed effectively etc. 

Several people told me I shouldn’t do this, but it’s one effective way that helped me scale up to 29 SFR in 9 years.

Hi BP community!  I currently House Hack in Everett, WA (near Seattle) and utilize FurnishedFinder for our basement ADU with great success. I have built up enough equity and savings and will start adding multiple rent...

It has good integration, is cost effective, and the direct booking feature is pretty good!

These are people whose full time job is to effectively manage the assets on behalf of the investors. 

However, in order to do this effectively, you have to have knowledge, experience, resources, and cash reserves in case things don't go exactly as planned.Hopefully this post was helpful to you in seeing a realistic example of how to purchase real estate without using your own money.