I can quickly try to address that for you.
Some of the large farms do have agronomists right on staff, as you identified, so they may well have their own in-house agronomic advice. Smaller farms, generally, have access to similar advice provided by independent agrology services. Most retailers would have a licensed agronomist on staff who is capable of delivering impartial advice.
As far as incorporating it right into the act goes, I'm not sure that's required. All of the products are registered, so then crop choices become more a matter of planning and the desires of individual farmers regarding the way they want to farm. When they do make choices, those are registered choices that are applied under strict guidelines. So I think advice is there for virtually any farm, big or small, that wants it or needs it.