A reliable lender can fund a loan within days, this opens the door to countless more deals allowing you to get the best possible price. 

Currently, I have 11 doors under contract. 

The companies that market themselves as "garage door companies" (residential) also almost always do commercial stuff as well, such as what you are looking at.

Considering the current circumstances, what is stopping me if I create brokerage that is offering buyer agent only with flat fee of 5k-10k ? My job is to submit bid and negotiate only.  Buyer go to open house directly.

Bragging about doors is just stroking the ego; I couldn't care less that a lot of people on here have more "doors" than me. 

While leasing is the front door to maintaining a property’s occupancy, renewing tenants is the back door.

Hey Aishan, I personally own 12-doors in Detroit and I live in California.

I live in California (Central Coast) and have built a 12-door portfolio in Detroit, which has been a great market for both cash flow and long-term potential.Detroit still offers properties well below the $150k mark, with strong rent-to-price ratios and a market that’s seeing growth in key areas.

Am I ok with this plan to ride up the appreciation, mortgage pay down and rising rents?

Now if your interpretation is cash flowing enough to quit your job that is another conversation.  20 or 30 properties at 1k a month a door, if managed properly is a great revenue mark in my book.