When old equipment pops up on small farms, it's usually someone operating on a small scale (~300ac or so), making a profit off land they own by keeping their costs down. Definitely not a great way to earn an income, and it probably doesn't cover their bills, but people do it.

Otherwise, the old equipment is typically used for odd jobs around the farm, like the use case of hauling produce you mentioned.

I'd agree that you see it less often with combines; they're a much more complicated machine.