The land return and the operator return has historically been about the same...40 years ago almost all farms were operated under a 50/50 agreement...landowner provides the land and pays for half the inputs (seed, fertilizer, etc), farmer provides the labor and machinery, and they split the crop. As landowners got further removed from the farm, cash rents became more common. Of course as machinery got bigger, some operators found they could pay higher rents and survive on a smaller margin over more acres. Some are good at finding that fine line, others go bankrupt. All of my landlords could probably get more rent, but like any business, some people prefer to deal with a local guy who does the work and takes care of things like he owns them himself.
All of this to say that if you own the land outright, you need about half as much to make the same profit, although that ignores the huge amount of capital required to make that purchase. The number of people who can purchase 750 acres of prime farmland and still want to do the work to operate it is vanishingly small. Quality central Illinois farmland sells for around $10,000/acre. The one field I own (by which I mean have a huge mortgage on) I expect to return about $250/acre this year, which doesn't even pay the interest on the note. That said, historically the return plus the appreciation has been at least as good as the SP500, and better if you can farm it yourself. The 'occupancy rate' is 100%, and it's not to hard to borrow money on it at a low rate.
You have to have a sharp pencil (good spreadsheets) and be comfortable with debt. My operating line is over $300,000 right now; thankfully it's down to around 3%. Then there's the mortgages, and the note on the combine.....
