That's just part of being a 1-man show and not something you can really avoid. If you hurt your hands you can't write code either so it doesn't save you.
I think it's more subtle than that. If you're in a service industry, and you can't serve, your cash flow stops. But if you're selling a product, then the product can keep generating income as long as it's valuable.
Obviously, you can think of yourself as being in the service of building a product, but that doesn't nullify the distinction. In fact, it can strengthen it: devote your initial efforts to building the sellable part of the product, so that you can actually sell it as soon as possible.
(This is the "capital" part of capitalism. Use labor to build capital, then profit off the capital.)
