In bygone times - when a landowner owned a patch of land, most likely he would hire a bunch of people (or order, I'm not sure) to farm the land. Today we all have a little patch of land - probably more than enough to give us each our fill of veggies. It'd be much cheaper to actually eat the crops we grow ourselves (and arguably healthier!). This is also a favorite tactic of those trying to survive the economic collapse of a country such as the US or UK.
The problem is to do with motivation and long term benefits versus short term payoff - a problem described excellently by this funny looking Israeli psychologist. Basically, you just need to attach something you love to the act of gardening - for more information check his video - very informative.
So if it's just a matter of incentivising, I say we do it, because hell, this is England - we don't even need to water the buggers!
