If you built an engine to fund your own Basic Income, how big that engine would need to be would depend on what it was doing. Building your own engine would mean you took control of your own protection. If you build a big engine (a muse), you can be your own patron. The engine would be the breadwinner, and you can focus on other things (if you want). A basic income engine would top your income up, or provide a buffer if that income disappeared for a bit. The return on capital is like its salary, or what is left over after salaries and costs are paid. You only know the return in advance if you lend the money, not if you invest it. If you lend it, it works for someone else... so it gets a (known) salary. Bonds and Fixed Income are lending. If it works for you, you get the profits (or losses). You can't remove risk. You can manage it. You can control what jobs your money gets, and that matters. Even a little engine, working hard... can.