When humans settled in Central America (about 15,000 years ago), they didn't have to domesticate the avocado. Pick these wonderful fruits from the tree and eat. Save the bones and plant wherever you want. No fiddling around raising fruitful varieties from wild ancestors. These are not millennia-long attempts to domesticate corn.
But how did it turn out so well? The fact is that all the breeding work, even before people, was done by someone else, simple, but big. And people came to everything ready.
To understand how this happened, let's observe how natural selection works in plants. To win the competition, they have to come up with clever breeding methods. The task is to spread the seeds over a large area.
If your seeds just fell and rotted under the tree, there is little use. Part of it will certainly germinate, an even smaller part will survive to adulthood. But the population of such trees is at great risk, because the parent is competing with its own children in a small area. You need to spread in all directions and occupy free spaces, then the species will flourish.