You are halfway proving my point and halfway showing that you don't get what can be done.
In the proving my point camp -- If your goal is to make money, please do not go into agriculture. Go into this arena if you goal is to improve the world. Money can be made elsewhere. Decisions that will impact the ability of people to live or die should NOT be based on the cash it will bring back into the hands of a startup.
And in the not getting it camp - 8 billion people each doing small tasks IS scale. Helping them do those tasks easier decreases the maintenance in their lives. Maybe it is a content-based app to see what has worked for other people. Maybe it is training materials to which people can subscribe. Maybe someone will sell modular garden box kits, with built-in drip irrigation, so you just plug in your hose and you have a system that can work in an arid climate. Or a set of 3D printer designs to print out your own hand tools for gardening.
All of those ideas can scale to be a profitable startup, and they are just off the top of my head. Who knows what could be developed if people really sat down and worked on it?
Finally, as far as gardening not making your life easier, I cannot help you with that. It isn't for everyone. But that is also the reason that communities work better than individuals. In our family, I do little of the farm work, but I make all of the money. It balances out. Find the right people to live with.