The community farm idea is pretty well established in the US. The idea works – you just pay in advance a set fee and this entitled you to a portion of the farm produce for the season. You come to the farm each weekend to collect your potion.
But community farms do not appeal to everyone. having been a member of one, I know the downsides. First, driving out to the farm every weekend can be a pain. And when you get here, you are not sure how much food you will be taking back. Usually for me it was way too much. So it is not surprising the this is more of a niche market mechanism.
Can one do better? La Ruche qui dit oui may be the answer. Very cool idea!