One of the things I'm surprised your article doesn't mention is the tax advantages of this type of investment. The depreciation and rehab costs (purchasing distressed properties) can be huge deductions to ones income taxes, which none of the others have. Then, along with the appreciation of real estate, this passive income investment outperforms the notion of maxing out my 401k as well.

Secondly – and this is just quibbling – I’d change that risk score. The risk of private equity is incredibly high and should be considerably riskier than bonds! You are providing a typically very large amount of capital to one business that you agree to have no control over, and the success or failure of that business over a locked, predefined term determines your return. And in the few deals I’ve negotiated for clients, my experience has been that there are often management fees, performance fees, etc. that may cut into your potential gains, anyway. You’re putting a lot of eggs in one basket, and promising an omelet or two to the management no matter what. You really need to be confident that you found the next Uber before you take this giant risk!
I actually spent a year and a half working as an affiliate marketer (mostly selling drumming related products – lessons, kits ect). 5 years on and one of my one page sites (which I’ve not touched) still nets me about $150 a month. I won’t be retiring off that but only really now appreciate the reverse pyramid approach to entrepreneurship (working for nothing initially but later being paid without effort!)
Think of yourself. What are your interests, passions, and hobbies? What is the one field to which you could contribute with added value? Think of this as your UVP (Unique Value Propositions), formulated in terms of “I could be the number one resource on (…)”. Insert your field of choice at the end of that proposition, then try to make it as narrow as possible.
Dividend or income investing has been gaining traction in recent years, particularly with the FIRE (i.e. Financial Independence, Retire Early) movement amongst the younger crowd to build up a passive income stream towards financial freedom. In this article, I highlight some of the main financial instruments you can deploy to build up a passive income stream for yourself.
Residual income is the best model for money generation. Once you master and build up one avenue, you can devote your time and money into another avenue. Eventually you start reaping the benefits of multiple residual income avenues. Enabling you to have complete financial and time freedom. I recommend to all people to build these types of asset models as they can greatly improve their life.