There are definitely economies of scale, but much of that can be captured by careful shoppers in say the 2-5000 acre range.  Especially if they are willing to actually work.  (Own sprayer, fertilizer rigs, NH3 bullet, etc. instead of calling the coop.)  At some point the math of buying seed cheaper starts to get offset by the headaches of keeping enough steering wheel holders around to make it all happen.  NOT saying it can't be accomplished well by the right personalities, but if you're putting 6 combines and 20 trucks out there and 90% of the work is being done by people who don't truly have a stake in the results it is a different dynamic from when the people doing most of the work are the ones getting the bills in their mailbox.