Right. So pretty much no one just up and says, "I want to be a farmer" and buys all the land and equipment they'll need to be successful. The land is usually inherited--which perpetuates a fundamental inefficiency.
The small farmer struggles because of something called economies of scale. All that equipment you mention? it can only be used so much by one person. An "agribusiness" farming thousands of acres at once won't have to buy a hundred times as much equipment, or expend a hundred times as much labor; it'll be more like a factor of five or ten. So the larger the farm, the more efficient it will be. (Also, it doesn't take twice as much effort to feed twice as many chickens; etc. etc. etc.)
The small farmer today is in a situation similar to as if there were only a few large auto manufacturers and most cars were built individually, by hand, one at a time. That would obviously make cars more expensive. You also mention problems with weather, prices of commodities, etc.---a large "agribusiness" can withstand those fluctuations; a small farmer may not be able to. (Not to mention political shitstorms like Trump's tariffs.)
These are the reasons why small farmers need to be subsidized. Small farming is inefficient and therefore costly. We would be better off as a society if we simply mass-produced food--the way we do almost every other consumer commodity--and helped farmers retrain for something more productive and ultimately, better for them. We wouldn't have to subsidize and support them.
As to objections that consolidating farm ownership would somehow affect our food supply--well, does anyone see the demand for food shrinking anytime soon? And when demand exists, supply is created.