harvesting is all handled with heavy equipment in corn production. You can't do that with tomatoes
I picked tomatoes and various other commercial vegetable crops in the early 80's (Australia), even back then they had mechanical harvesters. Hand picked tomatoes were the "cream of the crop", you pick them for about 2-4 weeks when the crop starts ripening, they are early to market and good quality so the farmer gets top dollar. However once the contract date* comes up for the entire crop to be harvested they were
mechanically harvested and ended up in cans and/or sauce bottles. Same with peas, a 1980's era pea harvester could pick the peas, pod them, wash, snap freeze, and bag them. Again "shop peas" were picked by hand and sold with their pods intact before the crop was at the optimum point for mechanical harvesting.
* - Large commercial vegetable crops are often sold on contract before they are even planted. The thing about tomatoes (other than copper coloured hands from the chemicals on them), is that a heavy summer downpour will cause a ripe tomato to swell to the point it's skin bursts. When such a scenario occurs all the mechanical harvesters are in full demand since everyone wants their tomato crop picked before it turns into tomato sauce and simply drips onto the ground. The farmer doesn't wait days/weeks for a harvester turns up. While it is raining he will be recruiting as many pickers as he can at a higher dollar rate per bin. From my experience the extra dollars did not make up for the futility of trying to fill a half ton wooden vegetable bin with tomato jelly.
As to TFA, unless they set up the whole plot as a hydroponic farm there's no way it's going to significantly reduce the food bill for ~1500 people. However I think that's the wrong way to look at the project, TFA compares the farm to a public park, pool or golf course in conventional towns, it's nice if such amenities can pay for their own upkeep but profit (in dollar terms) is not the goal. If nothing else the people in the community who use it will gain a much greater appreciation of where their food comes from and just how much planning, hard work and patience is involved in growing something edible and eating it before some other critter does.