The only thing I can think of are fruit trees. I'd like to plant seeds that can take care of themselves so a person only need pick them when they are in season.
There might be some, papaya's for example are pretty easy to grow if you're in a sub-tropical area or maybe berry bushes, but fruit trees all require quarterly feeding and yearly pruning to produce quality, bug-free fruit...But that's not too much work considering the rewards. Generally, everything requires payment of some kind to ensure the reward. If you don't feed the plants to ensure a healthy harvest, for example, then the bugs - whose work trade is pollination - will reap the harvest instead of you because they are doing something for the plant to ensure it's survival. That's how it works. The harvest tends to go to whoever does the service - bugs or people, plants don't care as long as it gets done, lol.
The only bypass I can think of is to work at something else you love, receive money, then buy edibles. That's "no work" gardening and it's great too!
Well, I was thinking of contributing to food solidarity by planting foods that can be neglected by a generation or so until someone who cares/appreciates it enough to continue. I've seen huuge mango trees and several papaya trees, avocado trees (and I KNOW they weren't cared for in the least) coconut palms, and even banana trees. Surely before there was farming people were benefiting from wild growing fruits and veggies?
It's not a bad idea - and some food trees are better than none - but a generation of neglect would mean the tree would grow to be enormous - past pruning for sure, making harvest really difficult and fruit quality iffy, unless it happened to be in an idyllic locale. Farming evolved from recognition of the obvious benefits from both an ag standpoint and a nutritional one.
I find wild fruits tend to be almost always unpalatable - very poor quality. Wild bananas, for example, are often fiberous and malformed. There are the odd exceptions, of course. Huge, old mango trees, borrowing your example, are nearly impossible to harvest fruit from - they just become giant bird feeders and bug incubators, which is great, but not immediately useful to hungry humans. But animals and bugs need food sources more than ever with disappearing habitat, so there is that.
There are things like katuk greens from Thailand, though they do get woody if not harvested regularly, they regenerate quickly from new starts. As for fruits, lilikoi (passionfruit), a vine, comes to mind...Hope others chime in with actual examples...With a lot of work, a neglected tree can probably be brought back up to edibility, but the keywords would definitely be work.
Some folks might not eat it, but you can plant Kale once and let it go to seed once and you will have Kale a very long time.