All of my previous properties were basically self-sustaining after I put in the initial contribution for purchase.

serves as a much safer investment, guaranteed return, and supports sustainable and community growth... 

This current bull market is not sustainable. 

@Angela Yan AirBNB has some nerve... can you believe they are going around bullying and suing cities/states to change their law to avoid them sustaining economic injuries?

Personally, I subscribe to the belief that as a young, ambitious hustler that sustains a high savings rate and invests systematically, that I have a far greater chance of compounding my returns and seeing outsized yields on my own business (real estate) right now, in the prime of life, than I will by allowing my investments to grow tax-free in index funds inside a Roth or 401(k). 

@Michael Le The SECs intent is not exactly to regulate the suicide rate due to an investor sustaining an investment loss.

With your curent steady income, you are used to a certain  life style which you cannot sustain if the steady income stops and you wait on houses to sell to make sporadic income .. 800K in retirement is not good enough if you want to maintain your $200K comobined income lifestyle for a long time.

Not that I think we're headed back to the 18% world of the early 80's but I don't know if 4% is sustainable either. 

You as investor are now the developer as well so in exchange for no cash flow up front your getting into the deal for a lower basis.The reality is as Curt has pointed out Many times on this site .. virtually no property anywhere in most of the US that is bought at market today can be sold within 2 to 5 years and not sustain a loss to capital..

Mid-cycle underwriting is the prudent way to estimate sustainable long-term returns.