You are confounding what's necessary for our survival from what people may want/desire.
Fruit/vegetables as we know today are largely unnecessary and a luxury we have learned to love. In fact, most of the love for it comes from rich people posturing about it because they have both the means to buy them and time to process them.
When you look at them objectively, they are extremely bad from an effort to payoff point of view, making them purely pleasure/status driven food.
If you clock back just a hundred years you will realize that most fruits/veggies were not even well known (at least not in their modern form) and not something to worry about.
The pizzas with tomato sauce were created because basically nobody wanted this weird unknown fruit coming from the new world. Brussel sprouts so bitter that most people could not even digest them properly and they were truly disgusting to eat (basically food poisoning).
I could go on and on but the fact is vegetable and fruits are something we do purely for pleasure, we have improved the farming efficiency on many of them but it hardly matters for most of them because more supply doesn't mean the surplus will necessarily get eaten (you need to have people both richer and with more time for that).
In fact, the whole "organic" thing is something related to this fact, it's rich people who wanted to raise the stakes for purchasing veggies because it has become "too cheap" with imports (thanks to low wage cost in exporting countries).
The proper farming that actually feeds the world has already scaled beyond the point where it's reasonable to try and squeeze more out of it. In fact, the problem has become to manage the thing economically because over supplying makes some extremely large operations with big fixed costs a gamble.