In addition to the criteria indicated by @Zach Wain, FHA has sustainable requirements for triplexes and quads which in San Diego pretty much means FHA loan is virtually only possible for SFR or duplex properties (triplexes and quads virtually never meet the sustainability requirement - I use virtually because I did acquire a quad 1.5 years ago that met FHA sustainability requirement).  

.- Death Benefit: policy in place provides an instant estate to heirs potentially income tax free as long as the policy is in force at the time of death- a store of liquid funds via "cash value," which can be borrowed from with out bank guidelines for any reason within 3-5 business days up to 90-95% of the current cash value however Its probably not recommended to borrow up to that high because you'd probably want the returns on your cash value to be "enough," to cover atleast the admin and cost of life insurance aspects of the policy so that the policy is self sustaining and kept in force.

With the increase in Ai " artificial Intel." people are becoming less and less of a requirement for business to survive.I believe that there are that many less sustainable jobs out there.

Do you think it's sustainable and/or justified? 

I have been noticing this for a while now, Wholesalers have increased their profit margins by over 300% in many Cases over the past few years. often the investor ends up with a fraction of that, not normal, nor sustainable.

I understand a big enough why will help you to sustain endurance but does anyone else have other ways they maintain their stamina?

I'm not looking for max cash flow and appreciation, but rather, a sustainable cash flow (roughly $200 per month for a managed SFH) in areas that generally produce quality renters who generally stay longer and take better care of the property (therefore not lowering the value of the neighborhood). 

Wanted to throw it out there and see if theres anyone out here in Hawaii with a sustainable business model strictly wholesaling.

That being said I would like to focus on getting a career started in the real estate industry in some form to sustain my living as I work towards becoming an investor myself.

In the last year my journey went from soil salinity control to general aquaculture, to mitigating water issues (pollution) and agricultural wastewater treatment and back to adaptable agriculture... then sustainable agriculture.